Improve Linux external terminal defaults

Related #5780

src/vs/workbench/parts/execution/electron-browser/terminal.ts

@@ -5,8 +5,16 @@
 import fs = require('fs');
 import env = require('vs/base/common/platform');
 
-// If the system is not debian but is on gnome, use gnome-terminal
-export const DEFAULT_TERMINAL_LINUX = (env.isLinux && !fs.existsSync('/etc/debian_version') && process.env.DESKTOP_SESSION === 'gnome') ? 'gnome-terminal' : 'x-terminal-emulator';
+let defaultTerminalLinux = 'xterm';
+if (env.isLinux) {
+	if (fs.existsSync('/etc/debian_version')) {
+		defaultTerminalLinux = 'x-terminal-emulator';
+	} else if (process.env.DESKTOP_SESSION === 'gnome' || process.env.DESKTOP_SESSION === 'gnome-classic') {
+		defaultTerminalLinux = 'gnome-terminal';
+	}
+}
+
+export const DEFAULT_TERMINAL_LINUX = defaultTerminalLinux;
 
 export const DEFAULT_TERMINAL_WINDOWS = 'cmd';