[LyX/master] Change preedit color settings

[Jürgen Spitzmüller]

Am Donnerstag, dem 16.07.2026 um 23:13 +0900 schrieb Koji Yokota:
> But preview still picks up the workarea background even though png’s
> background is transparent.

Yes, as I wrote. This should probably be fixed in PreviewLoader or
somewhere related.

Note further, if this is done, the foreground color will need to be
adapted as well to get proper contrast (as we do in the workarea).

-- 
Jürgen