diff --git a/src/css/editors-layout.css b/src/css/editors-layout.css
index efda79a..5e11c43 100644
--- a/src/css/editors-layout.css
+++ b/src/css/editors-layout.css
@@ -145,6 +145,9 @@
       cursor: col-resize;
       background-image: url(/assets/vertical.png);
       grid-area: 1 / 2 / 3 / 2;
+      position: relative;
+      box-shadow: -1px 0 0 0 var(--grid-background),
+        1px 0 0 0 var(--grid-background);
     }
     & .second-gutter,
     & .last-gutter {
diff --git a/src/grid.js b/src/grid.js
index ca86c21..9f992df 100644
--- a/src/grid.js
+++ b/src/grid.js
@@ -128,6 +128,7 @@ const setGridLayout = (type = '') => {
     ...(gutters.rowGutters && {
       rowGutters: gutters.rowGutters.map(formatGutters)
     }),
+    ...(type === 'tabs' && { columnMinSizes: { 0: 300 } }),
     minSize: 1,
     onDragEnd: saveGridTemplate
   }