First, if this is only happening with one termbase, reorganising that termbase may help. This is done by opening the termbase in MultiTerm and clicking 'Termbase Management' at the bottom of the left-hand pane, then Reorganise on the top toolbar:
Click through the Wizard then Close.
If it's happening with one or all termbases, does it still happen if you change from the default layout of the termbase window to, for example, flags layout?
Next, have you pinned Termbase Viewer or is it pop-out? Pinning it can stabilise things. Or unpinning then pinning - or resetting the whole view via the View tab>User Interface>Reset Window Layout.
Also important, do you have the correct version of MultiTerm for your version of Studio and have you made sure your version of MultiTerm is up to date? To do this, if you have automatic updates set, just open MultiTerm and accept any update offered. If you don't have automatic updates set, open MultiTerm and go to Help > Check for Updates.
Then, have you tried a Windows Repair of Studio via Control Panel? Instructions of how to do this, plus other ways to reset your Studio/MultiTerm setup, are given here:
Performing the first suggestion, a Windows Repair, is helpful with any heavy-duty software, especially after an update. BTW, you can find Control Panel by typing it into the 'Type here to search' box next to the Windows button bottom left of your screen.
Then repair MultiTerm:
Instructions for resetting Studio and MultiTerm are also in the above two links.
I would imagine running through the above will solve your problem. If these suggestions don't help, then try reinstalling.
If that does not work, you can then get free help with installation issues that are preventing you from working, pretty fast:
Fill in the form here:
Select 'Installation' from the 'Case type' dropdown and tell them that the problems occurred after installation and, most importantly, give your correct email address so that they can contact you.
I hope that you can find a solution in amongst all of the above!