treeview: option to hide twisties

src/vs/base/parts/tree/browser/tree.css

@@ -64,7 +64,7 @@
 
 /* Expansion */
 
-.monaco-tree .monaco-tree-rows > .monaco-tree-row.has-children > .content:before {
+.monaco-tree .monaco-tree-rows.show-twisties > .monaco-tree-row.has-children > .content:before {
 	content: ' ';
 	position: absolute;
 	display: block;
@@ -75,7 +75,7 @@
 	left: -16px;
 }
 
-.monaco-tree .monaco-tree-rows > .monaco-tree-row.expanded > .content:before {
+.monaco-tree .monaco-tree-rows.show-twisties > .monaco-tree-row.expanded > .content:before {
 	background-image: url('expanded.svg');
 }
 
@@ -109,11 +109,11 @@
 .vs-dark .monaco-tree-wrapper.drop-target,
 .vs-dark .monaco-tree .monaco-tree-row.drop-target														{ background-color: #383B3D !important; color: inherit !important; }
 
-.vs-dark .monaco-tree .monaco-tree-rows > .monaco-tree-row.has-children > .content:before {
+.vs-dark .monaco-tree .monaco-tree-rows.show-twisties > .monaco-tree-row.has-children > .content:before {
 	background-image: url('collapsed-dark.svg');
 }
 
-.vs-dark .monaco-tree .monaco-tree-rows > .monaco-tree-row.expanded > .content:before {
+.vs-dark .monaco-tree .monaco-tree-rows.show-twisties > .monaco-tree-row.expanded > .content:before {
 	background-image: url('expanded-dark.svg');
 }
 
@@ -131,11 +131,11 @@
 .hc-black .monaco-tree .monaco-tree-wrapper.drop-target,
 .hc-black .monaco-tree .monaco-tree-rows > .monaco-tree-row.drop-target												{ background: none !important; border: 1px dashed #f38518; }
 
-.hc-black .monaco-tree .monaco-tree-rows > .monaco-tree-row.has-children > .content:before	{
+.hc-black .monaco-tree .monaco-tree-rows.show-twisties > .monaco-tree-row.has-children > .content:before	{
 	background-image: url('collapsed-hc.svg');
 }
 
-.hc-black .monaco-tree .monaco-tree-rows > .monaco-tree-row.expanded > .content:before {
+.hc-black .monaco-tree .monaco-tree-rows.show-twisties > .monaco-tree-row.expanded > .content:before {
 	background-image: url('expanded-hc.svg');
 }
 

src/vs/base/parts/tree/browser/tree.ts

@@ -634,6 +634,7 @@ export interface ITreeConfiguration {
 
 export interface ITreeOptions {
 	twistiePixels?: number;
+	showTwistie?: boolean;
 	indentPixels?: number;
 	verticalScrollMode?: ScrollbarVisibility;
 	alwaysFocused?: boolean;

src/vs/base/parts/tree/browser/treeImpl.ts

@@ -64,6 +64,7 @@ export class Tree extends Events.EventEmitter implements _.ITree {
 		this.options = options;
 
 		this.options.twistiePixels = typeof this.options.twistiePixels === 'number' ? this.options.twistiePixels : 32;
+		this.options.showTwistie = this.options.showTwistie === false ? false : true;
 		this.options.indentPixels = typeof this.options.indentPixels === 'number' ? this.options.indentPixels : 12;
 		this.options.alwaysFocused = this.options.alwaysFocused === true ? true : false;
 		this.options.useShadows = this.options.useShadows === false ? false : true;

src/vs/base/parts/tree/browser/treeView.ts

@@ -504,6 +504,9 @@ export class TreeView extends HeightMap {
 
 		this.rowsContainer = document.createElement('div');
 		this.rowsContainer.className = 'monaco-tree-rows';
+		if (context.options.showTwistie) {
+			this.rowsContainer.className += ' show-twisties';
+		}
 
 		var focusTracker = DOM.trackFocus(this.domNode);
 		focusTracker.addFocusListener(() => this.onFocus());