View Port Guide/Grid Broke? Front, Back and Side Cameras A weird bug has appeared when I view through the default Front Back and Side camera views in Blender.  The square grid has an odd triangular effect (see image below).  This happened a couple of days ago and seems to have happened over night.  It doesn't effect modelling or renders (as far as I've noticed) but it's quite annoying to see - especially when I don't what's caused it.
This only seems to happen when viewing through cameras on the axis (numpad 1,3 and 7) and occasionally in the orthographic view (numpad 5). Normal perspective cameras don't have this issue.
I've looked around and can't find an answer to the issue though, if I'm honest, I don't know what to be searching for. I've also uninstalled the software, re-installed, reset preferences to factory setting etc. but still get the same result.
Has anyone had this issue before and resolved it?  I have accidentally changed a setting and not realised?
Thanks in advance
Use Alt + B to clear the clipping region, or use the menu View &gt; View Region &gt; Clipping Region.