Problem: Per title. Affected was Kodi Leia, but can happen to any Kodi. May also happen to other media players.
Explanation: This is a manifestation of the EDID issue (also known as the "quarter screen issue") where:
• Windows is losing the EDID for the display device (TV, projector) when the display is shut off or disconnected.
• Windows then resizes the screen resolution to the "default" display device, which forces Kodi to resize as well. This usually makes the Kodi display lower resolution (i.e. smaller).
• When the display is turned back on / reconnected, Windows re-acquires the EDID and changes back to the original resolution.
Kodi does not handle this gracefully.
The result is that Kodi gets "stuck" in the lower resolution, which manifests itself as a smaller (i.e. lower-resolution) window at the top-left corner of the screen.
Some people find that although Kodi is resized, it is still responsive, and so can be restored to full-screen mode via keystrokes. In my case, it also locks up, forcing me to kill and restart it each time.
This may or may not affect a HTPC directly connected to a TV. It may also seem to occur randomly, not every time.
The problem does appear to be exacerbated when:
• The HTPC is an Intel NUC; and/or
• There is a receiver between the HTPC and the display device; and/or
• The receiver is relatively old.
Keeping the receiver on full-time might not help since older receivers might interfere with EDID acquisition even when active.
This does not seem to occur on Android since Android doesn't handle EDID the same way. So if I had kept my Shield instead of getting a NUC, I probably wouldn't have this issue.(*)
You can also get a "Dr. HDMI". This is the same thing but more expensive.
These devices lock the EDID to >one< resolution only. So be sure the purchase the one that matches the intended resolution of your TV, projector or monitor.
(*) I exchanged the Shield for the NUC because the Shield didn't correctly support analog 7.1 audio.