macOS - restore use of hide and show for app.dock second instances (microsoft#259883)

Author: bpasero

src/vs/code/electron-main/main.ts

@@ -313,6 +313,11 @@ class CodeMain {
 				throw error;
 			}
 
+			// Since we are the second instance, we do not want to show the dock
+			if (isMacintosh) {
+				app.dock?.hide();
+			}
+
 			// there's a running instance, let's connect to it
 			let client: NodeIPCClient<string>;
 			try {
@@ -412,6 +417,11 @@ class CodeMain {
 			throw new ExpectedError('Terminating...');
 		}
 
+		// dock might be hidden at this case due to a retry
+		if (isMacintosh) {
+			app.dock?.show();
+		}
+
 		// Set the VSCODE_PID variable here when we are sure we are the first
 		// instance to startup. Otherwise we would wrongly overwrite the PID
 		process.env['VSCODE_PID'] = String(process.pid);