As you can see, the text and selection buttons in the synchronize window overlap. I haven't had those issues on version 12 and I tried the "Reset -> Factory-Reset To Default" button already.
Does not change the behavior.
I can switch to "Find" or "Duplicate Files" and the window looks fine then, but if I switch back to "Synchronize" it is messed up again. I did this first on the release edition and then on the newest beta version 13.6.3 x64. With the same results.
Close the sync panel, then paste this into the path field and push return:
/dopuslocaldata/state Data/sync.osd
That should locate and select the sync.osd config file.
Try renaming that file and then opening the sync panel.
If that fixes things, please zip the old file and send it to us via private message so we can try to work out what was going wrong. (It's a text file so you can open it in Notepad or the viewer pane to see what's in it.)