fix #53424 (#53425)

src/vs/base/browser/ui/grid/gridview.ts

@@ -27,14 +27,6 @@ export interface IView {
 	layout(width: number, height: number): void;
 }
 
-/*
-TODO:
-	- NEW: 	add a color to show a border where the sash is, similar to how other
-			widgets have a color (e.g. Button, with applyStyles). Challenge is that this
-			color has to be applied via JS and not CSS to not apply it to all views
-			NOT CSS
-*/
-
 export function orthogonal(orientation: Orientation): Orientation {
 	return orientation === Orientation.VERTICAL ? Orientation.HORIZONTAL : Orientation.VERTICAL;
 }

src/vs/workbench/browser/parts/editor/editorPart.ts

@@ -35,7 +35,7 @@ import { EditorDropTarget } from 'vs/workbench/browser/parts/editor/editorDropTa
 import { localize } from 'vs/nls';
 import { Color } from 'vs/base/common/color';
 import { CenteredViewLayout } from 'vs/base/browser/ui/centered/centeredViewLayout';
-import { IView } from 'vs/base/browser/ui/grid/gridview';
+import { IView, orthogonal } from 'vs/base/browser/ui/grid/gridview';
 
 interface IEditorPartUIState {
 	serializedGrid: ISerializedGrid;
@@ -414,7 +414,9 @@ export class EditorPart extends Part implements EditorGroupsServiceImpl, IEditor
 		const gridDescriptor = createSerializedGrid({
 			orientation: this.toGridViewOrientation(
 				layout.orientation,
-				(this.gridWidget.orientation === Orientation.VERTICAL) ? Orientation.HORIZONTAL : Orientation.VERTICAL // fix https://github.com/Microsoft/vscode/issues/52975
+				this.isTwoDimensionalGrid() ?
+					this.gridWidget.orientation :			// preserve original orientation for 2-dimensional grids
+					orthogonal(this.gridWidget.orientation) // otherwise flip (fix https://github.com/Microsoft/vscode/issues/52975)
 			),
 			groups: layout.groups
 		});
@@ -444,6 +446,17 @@ export class EditorPart extends Part implements EditorGroupsServiceImpl, IEditor
 		}
 	}
 
+	private isTwoDimensionalGrid(): boolean {
+		const views = this.gridWidget.getViews();
+		if (isGridBranchNode(views)) {
+			// the grid is 2-dimensional if any children
+			// of the grid is a branch node
+			return views.children.some(child => isGridBranchNode(child));
+		}
+
+		return false;
+	}
+
 	addGroup(location: IEditorGroupView | GroupIdentifier, direction: GroupDirection, options?: IAddGroupOptions): IEditorGroupView {
 		const locationView = this.assertGroupView(location);