diff --git a/components/lib/dropdown/Dropdown.js b/components/lib/dropdown/Dropdown.js
index 9be0ed8be8..75e87941eb 100644
--- a/components/lib/dropdown/Dropdown.js
+++ b/components/lib/dropdown/Dropdown.js
@@ -78,7 +78,7 @@ export const Dropdown = React.memo(
         };
 
         const isClearClicked = (event) => {
-            return DomHandler.hasClass(event.target, 'p-dropdown-clear-icon') || DomHandler.hasClass(event.target, 'p-dropdown-filter-clear-icon');
+            return DomHandler.isAttributeEquals(event.target, 'data-pc-section', 'clearicon') || DomHandler.isAttributeEquals(event.target.parentElement || event.target, 'data-pc-section', 'filterclearicon');
         };
 
         const onClick = (event) => {
@@ -93,7 +93,7 @@ export const Dropdown = React.memo(
                 return;
             }
 
-            if (DomHandler.hasClass(event.target, 'p-dropdown-clear-icon') || event.target.tagName === 'INPUT') {
+            if (isClearClicked(event) || event.target.tagName === 'INPUT') {
                 return;
             } else if (!overlayRef.current || !(overlayRef.current && overlayRef.current.contains(event.target))) {
                 DomHandler.focus(focusInputRef.current);
@@ -561,7 +561,7 @@ export const Dropdown = React.memo(
         };
 
         const scrollInView = () => {
-            const highlightItem = DomHandler.findSingle(overlayRef.current, 'li.p-highlight');
+            const highlightItem = DomHandler.findSingle(overlayRef.current, 'li[data-p-highlight="true"]');
 
             if (highlightItem && highlightItem.scrollIntoView) {
                 highlightItem.scrollIntoView({ block: 'nearest', inline: 'nearest' });
diff --git a/components/lib/dropdown/DropdownBase.js b/components/lib/dropdown/DropdownBase.js
index 392a9f80fc..52a8243731 100644
--- a/components/lib/dropdown/DropdownBase.js
+++ b/components/lib/dropdown/DropdownBase.js
@@ -28,6 +28,7 @@ const classes = {
     loadingIcon: 'p-dropdown-trigger-icon p-clickable',
     clearIcon: 'p-dropdown-clear-icon p-clickable',
     filterIcon: 'p-dropdown-filter-icon',
+    filterClearIcon: 'p-dropdown-filter-clear-icon',
     filterContainer: ({ clearIcon }) => classNames('p-dropdown-filter-container', { 'p-dropdown-clearable-filter': !!clearIcon }),
     filterInput: 'p-dropdown-filter p-inputtext p-component',
     list: ({ virtualScrollerOptions }) => (virtualScrollerOptions ? 'p-dropdown-items' : 'p-dropdown-items'),
diff --git a/components/lib/dropdown/DropdownPanel.js b/components/lib/dropdown/DropdownPanel.js
index 0009205c5f..7e0f9da89a 100644
--- a/components/lib/dropdown/DropdownPanel.js
+++ b/components/lib/dropdown/DropdownPanel.js
@@ -105,7 +105,8 @@ export const DropdownPanel = React.memo(
                 const itemGroupProps = mergeProps(
                     {
                         className: cx('itemGroup', { optionGroupLabel }),
-                        style
+                        style,
+                        'data-p-highlight': props.selected
                     },
                     getPTOptions('itemGroup')
                 );
@@ -140,11 +141,11 @@ export const DropdownPanel = React.memo(
                 const ariaLabel = localeOption('clear');
                 const clearIconProps = mergeProps(
                     {
-                        className: cx('clearIcon'),
+                        className: cx('filterClearIcon'),
                         'aria-label': ariaLabel,
                         onClick: () => props.onFilterClearIconClick(() => DomHandler.focus(filterInputRef.current))
                     },
-                    getPTOptions('clearIcon')
+                    getPTOptions('filterClearIcon')
                 );
                 const icon = props.filterClearIcon || <TimesIcon {...clearIconProps} />;
                 const filterClearIcon = IconUtils.getJSXIcon(icon, { ...clearIconProps }, { props });
diff --git a/components/lib/listbox/ListBoxItem.js b/components/lib/listbox/ListBoxItem.js
index e5a5b34eff..b5fdabb0cc 100644
--- a/components/lib/listbox/ListBoxItem.js
+++ b/components/lib/listbox/ListBoxItem.js
@@ -83,13 +83,13 @@ export const ListBoxItem = React.memo((props) => {
     const findNextItem = (item) => {
         const nextItem = item.nextElementSibling;
 
-        return nextItem ? (DomHandler.hasClass(nextItem, 'p-disabled') || DomHandler.hasClass(nextItem, 'p-listbox-item-group') ? findNextItem(nextItem) : nextItem) : null;
+        return nextItem ? (DomHandler.isAttributeEquals(nextItem, 'data-p-disabled', true) || DomHandler.isAttributeEquals(nextItem, 'data-pc-section', 'itemgroup') ? findNextItem(nextItem) : nextItem) : null;
     };
 
     const findPrevItem = (item) => {
         const prevItem = item.previousElementSibling;
 
-        return prevItem ? (DomHandler.hasClass(prevItem, 'p-disabled') || DomHandler.hasClass(prevItem, 'p-listbox-item-group') ? findPrevItem(prevItem) : prevItem) : null;
+        return prevItem ? (DomHandler.isAttributeEquals(prevItem, 'data-p-disabled', true) || DomHandler.isAttributeEquals(prevItem, 'data-pc-section', 'itemgroup') ? findPrevItem(prevItem) : prevItem) : null;
     };
 
     const content = props.template ? ObjectUtils.getJSXElement(props.template, props.option) : props.label;
@@ -108,7 +108,8 @@ export const ListBoxItem = React.memo((props) => {
             key: props.label,
             role: 'option',
             'aria-selected': props.selected,
-            'aria-disabled': props.disabled
+            'aria-disabled': props.disabled,
+            'data-p-disabled': props.disabled
         },
         getPTOptions('item')
     );
diff --git a/components/lib/mention/Mention.js b/components/lib/mention/Mention.js
index c201b38633..460634ca39 100644
--- a/components/lib/mention/Mention.js
+++ b/components/lib/mention/Mention.js
@@ -19,6 +19,8 @@ export const Mention = React.memo(
         const [focusedState, setFocusedState] = React.useState(false);
         const [searchingState, setSearchingState] = React.useState(false);
         const [triggerState, setTriggerState] = React.useState(null);
+        const [highlightState, setHighlightState] = React.useState([]);
+
         const elementRef = React.useRef(null);
         const overlayRef = React.useRef(null);
         const inputRef = React.useRef(props.inputRef);
@@ -37,10 +39,13 @@ export const Mention = React.memo(
 
         useHandleStyle(MentionBase.css.styles, isUnstyled, { name: 'mention' });
 
-        const getPTOptions = (item, suggestion) => {
+        const getPTOptions = (item, suggestion, options) => {
             return ptm(suggestion, {
                 context: {
                     trigger: triggerState ? triggerState.key : ''
+                },
+                state: {
+                    ...options
                 }
             });
         };
@@ -72,7 +77,13 @@ export const Mention = React.memo(
 
         const onOverlayEntering = () => {
             if (props.autoHighlight && props.suggestions && props.suggestions.length) {
-                DomHandler.addClass(listRef.current.firstChild, 'p-highlight');
+                setHighlightState((prevState) => {
+                    const newState = [...prevState];
+
+                    newState[0] = true;
+
+                    return newState;
+                });
             }
         };
 
@@ -92,13 +103,15 @@ export const Mention = React.memo(
         };
 
         const alignOverlay = () => {
-            const { key, index } = triggerState;
-            const value = inputRef.current.value;
-            const position = DomHandler.getCursorOffset(inputRef.current, value.substring(0, index - 1), value.substring(index), key);
-
-            overlayRef.current.style.transformOrigin = 'top';
-            overlayRef.current.style.left = `calc(${position.left}px + 1rem)`;
-            overlayRef.current.style.top = `calc(${position.top}px + 1.2rem)`;
+            if (triggerState) {
+                const { key, index } = triggerState;
+                const value = inputRef.current.value;
+                const position = DomHandler.getCursorOffset(inputRef.current, value.substring(0, index - 1), value.substring(index), key);
+
+                overlayRef.current.style.transformOrigin = 'top';
+                overlayRef.current.style.left = `calc(${position.left}px + 1rem)`;
+                overlayRef.current.style.top = `calc(${position.top}px + 1.2rem)`;
+            }
         };
 
         const onPanelClick = (event) => {
@@ -245,9 +258,19 @@ export const Mention = React.memo(
 
         const onInput = (event) => {
             props.onInput && props.onInput(event);
+            const isFilled = event.target.value.length > 0;
 
-            if (event.target.value.length > 0) DomHandler.addClass(elementRef.current, 'p-inputwrapper-filled');
-            else DomHandler.removeClass(elementRef.current, 'p-inputwrapper-filled');
+            if (isUnstyled()) {
+                DomHandler.setAttributes(elementRef.current, {
+                    'data-p-inputwrapper-filled': isFilled
+                });
+            } else {
+                if (isFilled) {
+                    DomHandler.addClass(elementRef.current, 'p-inputwrapper-filled');
+                } else {
+                    DomHandler.removeClass(elementRef.current, 'p-inputwrapper-filled');
+                }
+            }
         };
 
         const onKeyUp = (event) => {
@@ -264,7 +287,7 @@ export const Mention = React.memo(
 
         const onKeyDown = (event) => {
             if (overlayVisibleState) {
-                let highlightItem = DomHandler.findSingle(overlayRef.current, 'li.p-highlight');
+                let highlightItem = DomHandler.findSingle(overlayRef.current, 'li[data-p-highlight="true"]');
 
                 switch (event.which) {
                     //down
@@ -273,15 +296,33 @@ export const Mention = React.memo(
                             let nextElement = highlightItem.nextElementSibling;
 
                             if (nextElement) {
-                                DomHandler.addClass(nextElement, 'p-highlight');
-                                DomHandler.removeClass(highlightItem, 'p-highlight');
+                                const nextElementIndex = DomHandler.index(nextElement);
+                                const highlightItemIndex = DomHandler.index(highlightItem);
+
+                                setHighlightState((prevState) => {
+                                    const newState = [...prevState];
+
+                                    newState[nextElementIndex] = true;
+                                    newState[highlightItemIndex] = false;
+
+                                    return newState;
+                                });
+
                                 DomHandler.scrollInView(overlayRef.current, nextElement);
                             }
                         } else {
                             highlightItem = DomHandler.findSingle(overlayRef.current, 'li');
 
                             if (highlightItem) {
-                                DomHandler.addClass(highlightItem, 'p-highlight');
+                                const highlightItemIndex = DomHandler.index(highlightItem);
+
+                                setHighlightState((prevState) => {
+                                    const newState = [...prevState];
+
+                                    newState[highlightItemIndex] = true;
+
+                                    return newState;
+                                });
                             }
                         }
 
@@ -294,8 +335,18 @@ export const Mention = React.memo(
                             let previousElement = highlightItem.previousElementSibling;
 
                             if (previousElement) {
-                                DomHandler.addClass(previousElement, 'p-highlight');
-                                DomHandler.removeClass(highlightItem, 'p-highlight');
+                                const previousElementIndex = DomHandler.index(previousElement);
+                                const highlightItemIndex = DomHandler.index(highlightItem);
+
+                                setHighlightState((prevState) => {
+                                    const newState = [...prevState];
+
+                                    newState[previousElementIndex] = true;
+                                    newState[highlightItemIndex] = false;
+
+                                    return newState;
+                                });
+
                                 DomHandler.scrollInView(overlayRef.current, previousElement);
                             }
                         }
@@ -353,16 +404,31 @@ export const Mention = React.memo(
         }, [inputRef, props.inputRef]);
 
         useUpdateEffect(() => {
+            const hasSuggestions = props.suggestions && props.suggestions.length;
+
+            if (hasSuggestions) {
+                const newState = props.suggestions.map(() => false);
+
+                setHighlightState(newState);
+            }
+
             if (searchingState) {
-                props.suggestions && props.suggestions.length ? show() : hide();
+                hasSuggestions ? show() : hide();
                 overlayVisibleState && alignOverlay();
                 setSearchingState(false);
             }
         }, [props.suggestions]);
 
         useUpdateEffect(() => {
-            if (!isFilled && DomHandler.hasClass(elementRef.current, 'p-inputwrapper-filled')) {
-                DomHandler.removeClass(elementRef.current, 'p-inputwrapper-filled');
+            const _isUnstyled = isUnstyled();
+            const isInputWrapperFilled = _isUnstyled ? DomHandler.isAttributeEquals(elementRef.current, 'data-p-inputwrapper-filled', true) : DomHandler.hasClass(elementRef.current, 'p-inputwrapper-filled');
+
+            if (!isFilled && isInputWrapperFilled) {
+                _isUnstyled
+                    ? DomHandler.setAttributes(elementRef.current, {
+                          'data-p-inputwrapper-filled': false
+                      })
+                    : DomHandler.removeClass(elementRef.current, 'p-inputwrapper-filled');
             }
         }, [isFilled]);
 
@@ -373,14 +439,16 @@ export const Mention = React.memo(
         const createItem = (suggestion, index) => {
             const key = index + '_item';
             const content = props.itemTemplate ? ObjectUtils.getJSXElement(props.itemTemplate, suggestion, { trigger: triggerState ? triggerState.key : '', index }) : formatValue(suggestion);
+            const isSelected = highlightState[index];
 
             const itemProps = mergeProps(
                 {
                     key: key,
-                    className: cx('item'),
-                    onClick: (e) => onItemClick(e, suggestion)
+                    className: cx('item', { isSelected }),
+                    onClick: (e) => onItemClick(e, suggestion),
+                    'data-p-highlight': isSelected
                 },
-                getPTOptions(suggestion, 'item')
+                getPTOptions(suggestion, 'item', { selected: isSelected })
             );
 
             return (
diff --git a/components/lib/mention/MentionBase.js b/components/lib/mention/MentionBase.js
index 6964ba718c..d8ff46ae7d 100644
--- a/components/lib/mention/MentionBase.js
+++ b/components/lib/mention/MentionBase.js
@@ -2,7 +2,10 @@ import { ComponentBase } from '../componentbase/ComponentBase';
 import { classNames } from '../utils/Utils';
 
 const classes = {
-    item: 'p-mention-item',
+    item: ({ isSelected }) =>
+        classNames('p-mention-item', {
+            'p-highlight': isSelected
+        }),
     items: 'p-mention-items',
     panel: ({ props }) => classNames('p-mention-panel p-component', props.panelClassName),
     input: ({ props }) => classNames('p-mention-input', props.inputClassName),
diff --git a/components/lib/mention/mention.d.ts b/components/lib/mention/mention.d.ts
index d5bce95152..9e9a7d311a 100644
--- a/components/lib/mention/mention.d.ts
+++ b/components/lib/mention/mention.d.ts
@@ -86,6 +86,10 @@ export interface MentionState {
      * Current trigger state.
      */
     trigger: any;
+    /**
+     * For item, this is the state of the item.
+     */
+    selected?: boolean;
 }
 
 /**
diff --git a/components/lib/multiselect/MultiSelect.js b/components/lib/multiselect/MultiSelect.js
index 4441803d85..491557ffd0 100644
--- a/components/lib/multiselect/MultiSelect.js
+++ b/components/lib/multiselect/MultiSelect.js
@@ -267,7 +267,7 @@ export const MultiSelect = React.memo(
         };
 
         const scrollInView = () => {
-            const highlightItem = DomHandler.findSingle(overlayRef.current, 'li.p-highlight');
+            const highlightItem = DomHandler.findSingle(overlayRef.current, 'li[data-p-highlight="true"]');
 
             if (highlightItem && highlightItem.scrollIntoView) {
                 highlightItem.scrollIntoView({ block: 'nearest', inline: 'nearest' });
diff --git a/components/lib/passthrough/tailwind/index.js b/components/lib/passthrough/tailwind/index.js
index 8676c40446..2673181640 100644
--- a/components/lib/passthrough/tailwind/index.js
+++ b/components/lib/passthrough/tailwind/index.js
@@ -1286,7 +1286,11 @@ const Tailwind = {
         root: 'relative',
         panel: 'max-h-[200px] min-w-full overflow-auto bg-white dark:bg-gray-900 text-gray-700 dark:text-white/80 border-0 rounded-md shadow-lg',
         items: 'py-3 list-none m-0',
-        item: 'cursor-pointer font-normal overflow-hidden relative whitespace-nowrap m-0 p-3 border-0 transition-shadow duration-200 rounded-none dark:text-white/80 dark:hover:bg-gray-800 hover:text-gray-700 hover:bg-gray-200',
+        item: ({ state }) => ({
+            className: classNames('cursor-pointer font-normal overflow-hidden relative whitespace-nowrap m-0 p-3 border-0 transition-shadow duration-200 rounded-none dark:text-white/80 dark:hover:bg-gray-800 hover:text-gray-700 hover:bg-gray-200', {
+                'bg-blue-50 text-blue-700 dark:bg-blue-300 dark:text-white/80': state.selected
+            })
+        }),
         transition: TRANSITIONS.overlay
     },
     multiselect: {
diff --git a/components/lib/tree/UITreeNode.js b/components/lib/tree/UITreeNode.js
index 7b0340e9f4..12378ade11 100644
--- a/components/lib/tree/UITreeNode.js
+++ b/components/lib/tree/UITreeNode.js
@@ -803,7 +803,8 @@ export const UITreeNode = React.memo((props) => {
                 onDragEnter: onDragEnter,
                 onDragLeave: onDragLeave,
                 onDragStart: onDragStart,
-                onDragEnd: onDragEnd
+                onDragEnd: onDragEnd,
+                'data-p-highlight': isCheckboxSelectionMode() ? checked : selected
             },
             getPTOptions('content')
         );
diff --git a/components/lib/treeselect/TreeSelect.js b/components/lib/treeselect/TreeSelect.js
index 880cf0436a..0a3bec8790 100644
--- a/components/lib/treeselect/TreeSelect.js
+++ b/components/lib/treeselect/TreeSelect.js
@@ -95,7 +95,7 @@ export const TreeSelect = React.memo(
         };
 
         const onClick = (event) => {
-            if (!props.disabled && (!overlayRef.current || !overlayRef.current.contains(event.target)) && !DomHandler.hasClass(event.target, 'p-treeselect-close')) {
+            if (!props.disabled && (!overlayRef.current || !overlayRef.current.contains(event.target)) && !DomHandler.isAttributeEquals(event.target, 'data-pc-section', 'closebutton')) {
                 DomHandler.focus(focusInputRef.current);
                 overlayVisibleState ? hide() : show();
             }
@@ -341,7 +341,7 @@ export const TreeSelect = React.memo(
         };
 
         const scrollInView = () => {
-            const highlightItem = DomHandler.findSingle(overlayRef.current, '.p-treenode-content.p-highlight');
+            const highlightItem = DomHandler.findSingle(overlayRef.current, '[data-pc-section="content"][data-p-highlight="true"]');
 
             if (highlightItem && highlightItem.scrollIntoView) {
                 highlightItem.scrollIntoView({ block: 'nearest', inline: 'start' });