explorer: do not react on selection events if user is modifying selection via shift

fixes #66792

src/vs/workbench/electron-browser/commands.ts

@@ -115,7 +115,7 @@ export function registerCommands(): void {
 
 			const focus = list.getFocus() ? list.getFocus()[0] : undefined;
 			const selection = list.getSelection();
-			const fakeKeyboardEvent = new KeyboardEvent('keydown');
+			const fakeKeyboardEvent = new KeyboardEvent('keydown', { shiftKey: true });
 
 			if (selection && selection.indexOf(focus) >= 0) {
 				list.setSelection(selection.filter(s => s !== previousFocus), fakeKeyboardEvent);

src/vs/workbench/parts/files/electron-browser/views/explorerView.ts

@@ -64,7 +64,6 @@ export class ExplorerView extends ViewletPanel {
 	private decorationProvider: ExplorerDecorationsProvider;
 	private autoReveal = false;
 	private ignoreActiveEditorChange;
-	private previousSelection: ExplorerItem[] = [];
 
 	constructor(
 		options: IViewletPanelOptions,
@@ -294,9 +293,9 @@ export class ExplorerView extends ViewletPanel {
 			const selection = e.elements;
 			// Do not react if the user is expanding selection via keyboard.
 			// Check if the item was previously also selected, if yes the user is simply expanding / collapsing current selection #66589.
-			const wasMultiSelectedAndKeyboard = (e.browserEvent instanceof KeyboardEvent) && this.previousSelection.length > 1 && this.previousSelection.indexOf(selection[0]) >= 0;
-			this.previousSelection = selection;
-			if (selection.length === 1 && !wasMultiSelectedAndKeyboard) {
+
+			const shiftDown = e.browserEvent instanceof KeyboardEvent && e.browserEvent.shiftKey;
+			if (selection.length === 1 && !shiftDown) {
 				// Do not react if user is clicking on explorer items which are input placeholders
 				if (!selection[0].name) {
 					// Do not react if user is clicking on explorer items which are input placeholders