debug session become inactive when shutdown. Also more precise listeners for session changes

fixes #58308

src/vs/workbench/parts/debug/browser/debugActionItems.ts

@@ -198,15 +198,17 @@ export class FocusSessionActionItem extends SelectActionItem {
 
 		this.toDispose.push(attachSelectBoxStyler(this.selectBox, themeService));
 
-		this.debugService.getViewModel().onDidFocusStackFrame(() => {
+		this.toDispose.push(this.debugService.getViewModel().onDidFocusStackFrame(() => {
 			const session = this.debugService.getViewModel().focusedSession;
 			if (session) {
 				const index = this.debugService.getModel().getSessions().indexOf(session);
 				this.select(index);
 			}
-		});
+		}));
+
+		this.toDispose.push(this.debugService.onDidNewSession(() => this.update()));
+		this.toDispose.push(this.debugService.onDidEndSession(() => this.update()));
 
-		this.debugService.getModel().onDidChangeCallStack(() => this.update());
 		this.update();
 	}
 

src/vs/workbench/parts/debug/browser/debugActions.ts

@@ -131,7 +131,8 @@ export class StartAction extends AbstractDebugAction {
 		super(id, label, 'debug-action start', debugService, keybindingService);
 
 		this.toDispose.push(this.debugService.getConfigurationManager().onDidSelectConfiguration(() => this.updateEnablement()));
-		this.toDispose.push(this.debugService.getModel().onDidChangeCallStack(() => this.updateEnablement()));
+		this.toDispose.push(this.debugService.onDidNewSession(() => this.updateEnablement()));
+		this.toDispose.push(this.debugService.onDidEndSession(() => this.updateEnablement()));
 		this.toDispose.push(this.contextService.onDidChangeWorkbenchState(() => this.updateEnablement()));
 	}
 

src/vs/workbench/parts/debug/electron-browser/debugSession.ts

@@ -725,6 +725,7 @@ export class DebugSession implements IDebugSession {
 		dispose(this.rawListeners);
 		this.model.clearThreads(this.getId(), true);
 		this.model.removeSession(this.getId());
+		this.state = State.Inactive;
 		this.fetchThreadsScheduler = undefined;
 		if (this.raw) {
 			this.raw.disconnect();