This is a function for inserting placeables/tags in the target text that I have come to appreciate very much: By pressing Ctrl+Alt+RightArrow/LeftArrow, you step between the placeables/tags in the source element, forwards or backwards; each placeable/tag is highlighted in turn. When you come to the correct one, you just press Enter to insert it. In a segment with many placeables/tags, this is really useful.

However, suddenly what happened when I used that command was that instead of the expected result, the screen was briefly blackened and then, when it showed again, it was rotated! Totally bizarre and not useful at all.

The problem, it appeared, was to do with the Intel Video programming, which had been reset following an update of its driver. The solution was to inactivate the Intel Video shortcuts: right-click the screen, select Graphics Options > Shortcuts > Inactivate.

Probably a seldom occurring issue, but it may be good to know what to do if you happen to be affected.