8288893: Popup and its subclasses cannot input text from InputMethod

[beldenfox]

Input methods don’t work for text controls inside Popups. This PR fixes that.

Some background:

A PopupWindow always has an owner. The owner of the first Popup is a standard Window; I’ll refer to that as the root window. But a popup can show another popup (for example, a popup may contain a ComboBox which opens a menu which is also a Popup) resulting in a stack of PopupWindows.

Under the hood each PopupWindow has its own scene (this is not visible in the API). So if there’s a stack of PopupWindows there’s also a stack of scenes with the root window’s scene at the bottom.

The OS focus always stays with the root window (in part because JavaFX can’t move the OS focus when it’s embedded). This means a KeyEvent is initially fired at the focusOwner in the root window’s scene. Each PopupWindow in the stack uses an EventRedirector to refire that key event at its own focusOwner. In effect KeyEvents start processing at the top-most scene in the stack and work their way down to the root scene.

There are several reasons why Input Methods aren’t currently working for Popups.

• InputMethodEvents are not being redirected. This PR extends the EventRedirector to refire InputMethod events in the same way it refires KeyEvents.

• If a PopupWindow contains a TextInput control it will enable input method events on its scene which has no effect since that scene doesn’t have OS focus. If a PopupWindow wants to enable IM events it needs to do so on the root window’s scene. Put another way IM events should be enabled on the root scene if and only if one of the focusOwners in the scene stack requires IM events.

• The OS always retrieves the InputMethodRequests from the root window’s scene. InputMethodRequests should be retrieved from whichever focusOwner in the scene stack is processing InputMethodEvents.

In this PR the root scene creates an InputMethodStateManager object and shares it with all of the Popup scenes in the stack. Any time the focusOwner changes in a scene it tells the InputMethodStateManager so it can determine whether IM events should be enabled on the root scene. The root scene also calls on the InputMethodStateManager to retrieve InputMethodRequests so it can grab them from the appropriate Node in the scene stack.

This PR also fixes JDK-8334586. Currently the scene only enabled or disables IM events when the focusOwner changes. If a node’s skin is installed after it becomes focusOwner the scene won’t notice the change. In this PR the InputMethodStateManager installs listeners on the focusOwner to detect changes in the IM configuration.

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Progress

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Issue

• JDK-8288893: Popup and its subclasses cannot input text from InputMethod (Bug - P3)

Reviewing

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[bridgekeeper]

👋 Welcome back mfox! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[mlbridge]

Webrevs

• 02: Full - Incremental (ce980548)
• 01: Full - Incremental (43a4e6c4)
• 00: Full (cbae2c9b)

[beldenfox]

Converting to Draft. My testing macros weren't setup correctly and I missed a test.

[kevinrushforth]

/reviewers 2

[openjdk]

@kevinrushforth
The total number of required reviews for this PR (including the jcheck configuration and the last /reviewers command) is now set to 2 (with at least 1 Reviewer, 1 Author).