Only allow driveless mode for existing pads

www/common/sframe-common-outer.js

@@ -221,8 +221,11 @@ define([
                     }
                 } catch (e) { console.error(e); }
 
+                // NOTE: Driveless mode should only work for existing pads, but we can't check that
+                // before creating the worker because we need the anon RPC to do so.
+                // We're only going to check if a hash exists in the URL or not.
                 Cryptpad.ready(waitFor(), {
-                    noDrive: cfg.noDrive && AppConfig.allowDrivelessMode,
+                    noDrive: cfg.noDrive && AppConfig.allowDrivelessMode && currentPad.hash,
                     driveEvents: cfg.driveEvents,
                     cache: Boolean(cfg.cache),
                     currentPad: currentPad