Evenly spread out term panes on sash reset

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

@@ -91,6 +91,8 @@ export class SplitView implements IDisposable {
 
 	private _onDidSashChange = new Emitter<void>();
 	readonly onDidSashChange = this._onDidSashChange.event;
+	private _onDidSashReset = new Emitter<void>();
+	readonly onDidSashReset = this._onDidSashReset.event;
 
 	get length(): number {
 		return this.viewItems.length;
@@ -153,8 +155,10 @@ export class SplitView implements IDisposable {
 			const onSashChangeDisposable = onChange(this.onSashChange, this);
 			const onEnd = mapEvent<void, void>(sash.onDidEnd, () => null);
 			const onEndDisposable = onEnd(() => this._onDidSashChange.fire());
+			const onDidReset = mapEvent<void, void>(sash.onDidReset, () => null);
+			const onDidResetDisposable = onDidReset(() => this._onDidSashReset.fire());
 
-			const disposable = combinedDisposable([onStartDisposable, onSashChangeDisposable, onEndDisposable, sash]);
+			const disposable = combinedDisposable([onStartDisposable, onSashChangeDisposable, onEndDisposable, onDidResetDisposable, sash]);
 			const sashItem: ISashItem = { sash, disposable };
 
 			this.sashItems.splice(index - 1, 0, sashItem);

src/vs/workbench/parts/terminal/electron-browser/terminalTab.ts

@@ -42,6 +42,7 @@ class SplitPane implements IView {
 		container.removeChild((<any>this.instance)._wrapperElement);
 
 		this._splitView = new SplitView(container, { orientation });
+		this._splitView.onDidSashReset(() => this._resetSize());
 		this.layout(this._size);
 		this.orthogonalLayout(this.orthogonalSize);
 
@@ -78,6 +79,17 @@ class SplitPane implements IView {
 		this._onDidChange = anyEvent(...this._children.map(c => c.onDidChange));
 	}
 
+	private _resetSize(): void {
+		let totalSize = 0;
+		for (let i = 0; i < this._splitView.length; i++) {
+			totalSize += this._splitView.getViewSize(i);
+		}
+		const newSize = Math.floor(totalSize / this._splitView.length);
+		for (let i = 0; i < this._splitView.length - 1; i++) {
+			this._splitView.resizeView(i, newSize);
+		}
+	}
+
 	public remove(): void {
 		if (!this._parent) {
 			return;