No horizontal scrollbars after toggling side by side diff view (fix #64090)

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

@@ -1373,6 +1373,10 @@ export class EditorGroupView extends Themable implements IEditorGroupView {
 	layout(width: number, height: number): void {
 		this.dimension = new Dimension(width, height);
 
+		// Ensure editor container gets height as CSS depending
+		// on the preferred height of the title control
+		this.editorContainer.style.height = `calc(100% - ${this.titleAreaControl.getPreferredHeight()}px)`;
+
 		// Forward to controls
 		this.titleAreaControl.layout(new Dimension(this.dimension.width, this.titleAreaControl.getPreferredHeight()));
 		this.editorControl.layout(new Dimension(this.dimension.width, this.dimension.height - this.titleAreaControl.getPreferredHeight()));

src/vs/workbench/browser/parts/editor/media/editorgroupview.css

@@ -100,10 +100,6 @@
 
 /* Editor */
 
-.monaco-workbench > .part.editor > .content .editor-group-container > .editor-container {
-	height: calc(100% - 35px); /* below title control */
-}
-
 .monaco-workbench > .part.editor > .content .editor-group-container.empty > .editor-container  {
 	display: none;
 }

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

@@ -322,8 +322,6 @@ export abstract class TitleControl extends Themable {
 		return keybinding ? keybinding.getLabel() : void 0;
 	}
 
-	//#region ITitleAreaControl
-
 	abstract openEditor(editor: IEditorInput): void;
 
 	abstract closeEditor(editor: IEditorInput): void;
@@ -347,8 +345,6 @@ export abstract class TitleControl extends Themable {
 	abstract updateStyles(): void;
 
 	layout(dimension: Dimension): void {
-		// Optionally implemented in subclasses
-
 		if (this.breadcrumbsControl) {
 			this.breadcrumbsControl.layout(undefined);
 		}
@@ -364,8 +360,6 @@ export abstract class TitleControl extends Themable {
 
 		super.dispose();
 	}
-
-	//#endregion
 }
 
 registerThemingParticipant((theme: ITheme, collector: ICssStyleCollector) => {