On the latest release of Windows 10 the checkboxes so prevalent in BRU are not being displayed properly. All the boxes, whether selected or un-selected all appear as black squares.
Likewise, the issue did not occur on the prior version of Win10?
Might your video drivers have updated? Are you using a particular windows "theme" Any change if you restart your computer into Safe Mode?
I have seen similar before, not in BRU but elsewhere, though I am on Win7, & I also have Windows "Aero" disabled, so I am more apt to run into a similar situation.