[LyX/master] Introducing OnTheSpot-style input method editing & IME integration

[Pavel Sanda]

On Wed, Jan 29, 2025 at 11:48:07AM +0900, Yokota K. wrote:
> I could not reproduce it on Mac, but judging from the fact that the problem occurs when a focus changes, it can be related to calls of inputItemTransform() or setInputItemTransform functions in src/frontends/qt/GuiWorkArea.cpp.

It's perfectly reproducible here.
The easiest way: 
0. Setup your linux windows manager "Focus follows mouse"
1. Load some manual in lyx (file needs to be in read-only mode) and select random text
2. Hold Alt key and move focus out of lyx window
3. Selected text is removed (or rather CT-deleted), buffer is not set to modified

Notes:
- Debug output shows this happens whenever GuiWorkArea.cpp (2e7): GuiWorkArea::focusOutEvent(): 0x55946b6d7a40  happens.
- Sometimes it happens without focus change while the debug shows: GuiInputMethod.cpp (694): Responded to query Qt::ImCursorRectangle =  x:236 y:161 w:1 h:26
- I don't see debug messages around (set)inputItemTransform() methods, they might not be involved here

> If selection is not related, the same phenomena can happen on 2.4.x series, since the modification in GuiWorkArea was already made in LyX 2.4.2.

I can not reproduce with 2.4.x.

Pavel