I had this problem on 42.3 but hoped it would be gone after I fresh-installed Leap 15. The issue is simple: I open up a GTK app (such as LibreOffice 5 in the GTK UI or Inkscape), use it for even up to several hours, then my mouse cursor freezes, my screen freezes, my entire computer freezes, and I have to hold down the power button for five seconds to reboot it. Seriously--not even Magic SysRq + REISUB works. This bug kind of ruins my workflow since Inkscape is my go-to vector illustrator, and I'm sure I'm not alone. Thank you so much for your help!

PC specs if they help:

HP 15t laptop (2014)
Intel Pentium N3540 w/ Intel HD Graphics
4GB DDR3-1333 RAM

I'm using BtrFS for the root partition and XFS for the home partition.