Did you have this problem before or is it very recent.
In other words, is this problem new?
Do you have the same problem on another post? You can also post your part and your plan so that we can see if we have the pb (in this case make a pack and go so that we have the links between the parts and the plan)
With automatic Windows updates, it can happen that some drivers become obsolete in some programs.
Because let's not forget that SW is thousands of small programs that are called depending on what you do.
If the person who wrote this piece of program mishandled the display conditions, you may have a problem.
One way would be to update the mouse driver (especially if it's a slightly exotic mouse).
It must have been 1 year, following an update I think, since then I've dealt with it. I have a little time to watch now.
On the other workstations of the Zbook design office (same hardware, same configuration (in theory) managed by the info department), no problem with the same drawings.
Ask one of your colleagues to make the plan in question to check that it is not the MEP file that is corrupted.
If it works elsewhere and your MEP file is not faulty, then ask the IT department to look at your machine and compare the version and driver levels against the others.
Also beware of files imported from online providers, it happened to me once that I could not use the downloaded file.