debug: respect message box size when layouting call stack view

fixes #1362

src/vs/workbench/parts/debug/browser/debugViewlet.ts

@@ -272,6 +272,11 @@ class CallStackView extends viewlet.CollapsibleViewletView {
 		}));
 	}
 
+	public layoutBody(size: number): void {
+		const sizeWithRespectToMessageBox = this.messageBox && !this.messageBox.hidden ? size - 27 : size;
+		super.layoutBody(sizeWithRespectToMessageBox);
+	}
+
 	private renderMessageBox(container: HTMLElement): void {
 		this.messageBox = document.createElement('div');
 		dom.addClass(this.messageBox, 'debug-message-box');

src/vs/workbench/parts/debug/browser/media/debugViewlet.css

@@ -68,6 +68,7 @@
 	background: #F6F5D2;
 	padding: 0.4em 1em .3em 1.9em;
 	font-size: 8pt;
+	line-height: 18px;
 
 	-webkit-user-select: text;
 	-moz-user-select: text;