Then test with trunk after revisions r55269 + r55277. They fixed issue:
https://bugs.freepascal.org/view.php?id=31981
which was about wrong options for a docked IDE. This issue could be related. The revisions will be merged to fixes_1_8.
No it isn't, when loading lazarus default (no-AD) all AD-desktop-settings are deleted (they only should be deactivated).
I just tested the issue again. In my point of view it is working correct:
If you make changes in a undocked (default) IDE in the settings, these settings are taken to a initially docked desktop after installing package AnchorDockedDsgn. You can now make changes in this new created (default docked) desktop. The last unused (default) desktop isn't deleted and not changed (see Mainmenu -> Tools -> Desktops ...).
If you now uninstall package AnchorDockedDsgn, the previous default desktop is loaded again. The docked desktops are deleted and this is correct, as they come with the package AnchorDockedDsgn (all things that a package installs have to be removed, if the package is uninstalled).
If you later want to reuse docked settings, you have do export and import these docked desktops. Of course this is not working now (
https://bugs.freepascal.org/view.php?id=29200). So the current workaround is to make a copy of your environmentoptions.xml and use it after reinstalling AnchorDockedDsgn, don't uninstall that package or adapt your divergent settings from your default desktop after package reinstalling.