Tables: activating an ID (e.g. clicking button inside) column doesn't…

… prevent columns output flags from having ImGuiTableColumnFlags_IsHovered set. (ocornut#2957)

docs/CHANGELOG.txt

@@ -191,6 +191,8 @@ Other Changes:
   io.HoverDelayNormal (default to 0.30f) and io.HoverDelayFast (default to 0.10f). (#1485)
 - IsItemHovered: Added ImGuiHoveredFlags_NoSharedDelay to disable sharing delays between itemm,
   so moving from one item to a nearby one will requires delay to elapse again. (#1485)
+- Tables: activating an ID (e.g. clicking button inside) column doesn't prevent columns
+  output flags from having ImGuiTableColumnFlags_IsHovered set. (#2957)
 - Tables,Columns: fixed a layout issue where SameLine() prior to a row change would set the
   next row in such state where subsequent SameLine() would move back to previous row.
 - Tabs: Fixed a crash when closing multiple windows (possible with docking only) with an

imgui.h

@@ -23,7 +23,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM > 12345')
 #define IMGUI_VERSION               "1.89 WIP"
-#define IMGUI_VERSION_NUM           18830
+#define IMGUI_VERSION_NUM           18831
 #define IMGUI_HAS_TABLE
 #define IMGUI_HAS_VIEWPORT          // Viewport WIP branch
 #define IMGUI_HAS_DOCK              // Docking WIP branch

imgui_tables.cpp

@@ -936,11 +936,19 @@ void ImGui::TableUpdateLayout(ImGuiTable* table)
             width_remaining_for_stretched_columns -= 1.0f;
         }
 
+    // Determine if table is hovered which will be used to flag columns as hovered.
+    // - In principle we'd like to use the equivalent of IsItemHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem),
+    //   but because our item is partially submitted at this point we use ItemHoverable() and a workaround (temporarily
+    //   clear ActiveId, which is equivalent to the change provided by _AllowWhenBLockedByActiveItem).
+    // - This allows columns to be marked as hovered when e.g. clicking a button inside the column, or using drag and drop.
     ImGuiTableInstanceData* table_instance = TableGetInstanceData(table, table->InstanceCurrent);
     table->HoveredColumnBody = -1;
     table->HoveredColumnBorder = -1;
     const ImRect mouse_hit_rect(table->OuterRect.Min.x, table->OuterRect.Min.y, table->OuterRect.Max.x, ImMax(table->OuterRect.Max.y, table->OuterRect.Min.y + table_instance->LastOuterHeight));
+    const ImGuiID backup_active_id = g.ActiveId;
+    g.ActiveId = 0;
     const bool is_hovering_table = ItemHoverable(mouse_hit_rect, 0);
+    g.ActiveId = backup_active_id;
 
     // [Part 6] Setup final position, offset, skip/clip states and clipping rectangles, detect hovered column
     // Process columns in their visible orders as we are comparing the visible order and adjusting host_clip_rect while looping.