Delay animating until content is prepared to prevent weird flying elements.

src/vs/workbench/contrib/welcome/gettingStarted/browser/gettingStarted.css

@@ -12,11 +12,14 @@
 	width: 100%;
 	height: 100%;
 	position: absolute;
-	transition: left 0.25s, opacity 0.25s;
 	left: 0;
 	top: 0;
 }
 
+.monaco-workbench .part.editor > .content .walkThroughContent .gettingStartedContainer.animationReady .gettingStartedSlide {
+	transition: left 0.25s, opacity 0.25s;
+}
+
 .monaco-workbench .part.editor > .content .walkThroughContent .gettingStartedContainer .gettingStartedSlide.categories {
 	display: flex;
 	flex-direction: column;

src/vs/workbench/contrib/welcome/gettingStarted/browser/gettingStarted.ts

@@ -258,6 +258,7 @@ export class GettingStartedPage extends Disposable {
 		} else {
 			tasksSlide.classList.add('next');
 		}
+		setImmediate(() => assertIsDefined(container.querySelector('.gettingStartedContainer')).classList.add('animationReady'));
 	}
 
 	private layout() {