RAD Studio has a great ecosystem of third party vendors, providing both components and IDE plugins, software that lives within the IDE itself. In RAD Studio 10.4.1, we made some changes to our docked windows support (a docked window is a pane like the Structure, Projects or Palette views.) This change can create issues with IDE plugins that use their own custom docked windows.
One example of such Plugin is Bookmarks, distributed by Embarcadero, but also other commonly used third-party plugins.
The issue can appear as access violations when using the plugins or IDE, or as the plugin docked window showing at an unexpected time, and possibly other unexpected behaviour.
The issue is resolved when the plugin is recompiled for 10.4.1, and we are communicating with our tech partners to ask that they distribute an updated recompiled version of any IDE plugin they distribute for 10.4.1. We will also update our own IDE plugin, Bookmarks, to a 10.4.1 compatible version, downloadable via GetIt. This should be available within 24 hours.
We recommend uninstalling IDE plugins before upgrading to 10.4.1, and then re-installing the 10.4.1 versions of your IDE plugins.