theming - fix border issue when moving groups

extensions/theme-abyss/themes/abyss-color-theme.json

@@ -290,6 +290,7 @@
 		"editorSideBySideBorder": "#10192c",
 		"panelBorderTopColor": "#2b2b4a",
 		"statusBarBackground": "#10192c",
+		"statusBarNoFolderBackground": "#10192c",
 		"activityBarBackground": "#051336",
 		"sideBarBackground": "#060621",
 		"titleBarActiveBackground": "#10192c",

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

@@ -734,6 +734,7 @@ export class EditorGroupsControl extends Themable implements IEditorGroupsContro
 		}
 
 		this.layoutContainers();
+		this.updateStyles();
 	}
 
 	public setGroupOrientation(orientation: GroupOrientation): void {
@@ -928,10 +929,8 @@ export class EditorGroupsControl extends Themable implements IEditorGroupsContro
 			silo.style('background-color', this.getColor(editorBackground));
 
 			// Border
-			if (index > Position.ONE) {
-				silo.style('border-left-color', this.getColor(EDITOR_GROUP_BORDER_COLOR));
-				silo.style('border-top-color', this.getColor(EDITOR_GROUP_BORDER_COLOR));
-			}
+			silo.style('border-left-color', index > Position.ONE ? this.getColor(EDITOR_GROUP_BORDER_COLOR) : null);
+			silo.style('border-top-color', index > Position.ONE ? this.getColor(EDITOR_GROUP_BORDER_COLOR) : null);
 		});
 
 		// Title control