Looks like a bug in Corona bitmap to me - what Windows UI scale do you use? And what is your screen resolution? Which version of 3ds Max?
Could you try this without any UI scaling, just to see whether this avoids the problem?
Another thing you could try is to detach the parameter panel by dragging it off at the two horizontal dashed lines at the top - does that make any difference?
Martin Breidt
http://scripts.breidt.net→ please 'Like' posts that are helpful; if a post answers your question please click the "Accept Solution" button.