Dragging a window icon in the pager from one desktop to another no longer moves the related window from that desktop to the other. (Or possibly there is some option that needs to be set?)
The new system to select which desktop to move a window between desktops to is not a good one. To move a window one has to select Top-Decoration->Desktops and tick the (additional) desktop that the window should be on, then do this again to untick the current desktop.
If Firefox is quitted and then restarted, it no longer restores its windows to the desktops that they were on before it was quitted.
Discover no longer gives much info about packages being upgraded. For my current upgrade it simply reports "System Upgrade / 62 packages to upgrade". This is not useful in getting info about unfamiliar packages or finding out whether a reboot is desirable.
Some .jpg files are not previewed on the Desktop. I have no idea about why some are previewed and others are not.