Use items width to compute overflow

src/vs/base/browser/ui/toolbar/toolbar.ts

@@ -97,6 +97,14 @@ export class ToolBar {
 		return this.actionBar.getContainer();
 	}
 
+	public getItemsWidth(): number {
+		let itemsWidth = 0;
+		for (let i = 0; i < this.actionBar.length(); i++) {
+			itemsWidth += this.actionBar.getWidth(i);
+		}
+		return itemsWidth;
+	}
+
 	public setAriaLabel(label: string): void {
 		this.actionBar.setAriaLabel(label);
 	}

src/vs/workbench/browser/parts/panel/media/panelpart.css

@@ -30,10 +30,6 @@
 	border-left-style: solid;
 }
 
-.monaco-workbench > .part.panel > .composite.title > .title-actions {
-	flex-grow: 0;
-}
-
 .monaco-workbench > .part.panel > .title > .title-actions .monaco-action-bar .action-item .action-label {
 	outline-offset: -2px;
 }

src/vs/workbench/browser/parts/panel/panelPart.ts

@@ -43,7 +43,6 @@ export class PanelPart extends CompositePart<Panel> implements IPanelService {
 	private blockOpeningPanel: boolean;
 	private compositeBar: CompositeBar;
 	private dimension: Dimension;
-	private toolbarWidth = new Map<string, number>();
 
 	constructor(
 		id: string,
@@ -258,11 +257,7 @@ export class PanelPart extends CompositePart<Panel> implements IPanelService {
 		if (!activePanel) {
 			return 0;
 		}
-		if (!this.toolbarWidth.has(activePanel.getId())) {
-			this.toolbarWidth.set(activePanel.getId(), this.toolBar.getContainer().offsetWidth);
-		}
-
-		return this.toolbarWidth.get(activePanel.getId());
+		return this.toolBar.getItemsWidth();
 	}
 }