8319880: JTextField text selection doesn't stop if ended during loss of window focus

[anass-baya]

Analysis :
The issue is that on Win32, if the window is not active, we dont receive mouse events because we release the capture
So the problem is the following:
We start selecting text from the right to the extreme left.
Then we switch to another window( the window lose focus ), and we release the mouse
But when we return to the window, the caret drag is still active and does not stop. as the window did not recieved the mouse release event

Proposed fix:
In the Caret class, we added a logic to ignore the drag if the focus was lost due to window switching unless a new mouse press happens

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Issue

• JDK-8319880: JTextField text selection doesn't stop if ended during loss of window focus (Bug - P3)

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• 03: Full - Incremental (1488e2dc)
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• 01: Full - Incremental (0d4722dc)
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[azuev-java]

These calls are still need to happen on EDT.

[anass-baya]

OKay, thanks

[prsadhuk]

should we set dragActive here? it's just mousePressed, in which case all mousePress event will have dragActive set.
I guess it should be set in mouseDragged and reset in mouseReleased, no?

[anass-baya]

The issue is that when we start selecting text and then switch to another window, our window loses focus. After losing focus, we no longer receive mouse events. So when we release the mouse button in the other window and then switch back, our window thinks the drag is still happening because it never received the mouse-release event.

To fix this, we added logic to stop the drag as soon as we lose focus. And when we regain focus, since we don’t know whether the mouse was released or not, we require a new mouse-press before allowing dragging again. We also added logic to ignore outdated drag events: any drag event that happened before the last mouse-press is considered outdated and is ignored.

So now the behavior matches what we see in native apps like Notepad. @aivanov-jdk asked to check how a native Windows app behaves in this situation and to make our behavior consistent with that.

This logic does not affect the behavior on macOS.