Mint 19.3 XFCE - Appearance changes won't stay in place

[br1anstorm]

I have long used 19.1 XFCE on my main laptop and have been content with most of the default settings for icons, taskbar and the rest of the display. Out of interest I have also recently tried LMDE4 on another machine and have been happy with its appearance (my first encounter with Cinnamon) out-of-the-box.

I have just installed 19.3 XFCE on a "spare" laptop, and as the display, icons and themes were a bit different and unfamiliar, I set about changing and customising them from the options offered under the Appearance settings. Nothing too radical: I think I chose the standard Mint-Y theme and icons after looking briefly at some of the others. I also had to add an icon to the essential 'Start' button on the taskbar which launches the Whisker menu, as it was blank. I chose one of the standard Mint logos. Finally I chose a wallpaper as there wasn't one in place. Again, a standard image.

I thought that was it, sorted. But - frustratingly - these changes don't seem to be "saved". After I shut down and then boot up again, the changes I've made have vanished... and the display has reverted to something else (a default?). Why is this happening? I'm puzzled.

UPDATE: After a day spent in further contemplation, and as there have been views but no comments on this post, I perhaps need to redirect readers to a thread I've just posted in the "Installation" sub-forum which adds further details and - possibly - points towards an explanation. It's all to do with the fact that this Mint 19.3 is dual booted with MX Linux (and in a way which may well be the reason for the problem). See this post at viewtopic.php?f=46&t=353369