Show collapse icon in custom tree views

src/vs/workbench/browser/parts/views/customView.ts

@@ -308,7 +308,7 @@ export class CustomTreeView extends Disposable implements ITreeView {
 
 	getPrimaryActions(): IAction[] {
 		if (this.showCollapseAllAction) {
-			const collapseAllAction = new Action('vs.tree.collapse', localize('collapseAll', "Collapse All"), 'monaco-tree-action collapse-all', true, () => this.tree ? new CollapseAllAction<ITreeItem, ITreeItem, FuzzyScore>(this.tree, true).run() : Promise.resolve());
+			const collapseAllAction = new Action('vs.tree.collapse', localize('collapseAll', "Collapse All"), 'monaco-tree-action codicon-collapse-all', true, () => this.tree ? new CollapseAllAction<ITreeItem, ITreeItem, FuzzyScore>(this.tree, true).run() : Promise.resolve());
 			return [...this.menus.getTitleActions(), collapseAllAction];
 		} else {
 			return this.menus.getTitleActions();
@@ -921,4 +921,3 @@ class TreeMenus extends Disposable implements IDisposable {
 		return result;
 	}
 }
-