I get this on my laptop (not my DAW) sometimes. It does OCCASIONALLY happen on my DAW and I'm pretty sure any computer I've ever worked on has had this happen at some point or another sporadically.
I just chalk it up to annoying Windows graphical glitching. For me just waiting for a minute to let the computer get it's panties unbunched or just "mousing around" a bit usually makes it come back. Otherwise closing and restarting the program should do it and a reboot should definitely do it.
BUT if it persists there may be may be something wonky going on with windows and/or your graphics driver and/or if you use a special mouse/pointing device that requires drivers (like my Kensignton Expert Mouse does or some wireless/bluetooth HID's do) the problem could be there.
Check for driver updates for graphic cards and mice/trackballs. If wireless maybe check your batteries or switch to a wired mouse.
Just some general ideas.
Cheers and welcome.