[Erwan MATHIEU (wawanbreton)]

We recently introduced new mechanisms to make sure all the dialogs in the front-end are created, displayed and destroyed the same way. This PR ensures all the remaining dialogs are now processed properly. This also ensures that the dialog-centering hack on Linux works for all of them.

• Make the QtApplication singleton accessible to QML
• Add a mainWindow property to the QtApplication
• Make UM.Dialog take the main window as transient parent by default, so that modality and centering always work

Comes with Ultimaker/Cura#21876
CURA-13376

[github-actions]

Test Results

2 404 tests  ±0   2 389 ✅ ±0   22s ⏱️ -1s
    1 suites ±0      15 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit 46562ae. ± Comparison against base commit 57054bc.

♻️ This comment has been updated with latest results.

[Copilot]

🟡 Changes recommended

The constant main-window property prevents surviving dialogs from updating their transient parent after a QML reload.

1 open issue

• Use a notifying signal for transientParent after main window replacement · New

What changed in this PR

Standardizes dialog parenting in Uranium to support consistent modality and Linux centering, complementing the dialog lifecycle updates in Cura PR #21876.

Changes:

• Exposes QtApplication and its main window to QML.
• Moves default transient parenting from createQmlSubWindow() into UM.Dialog.

File	Description
UM/​Qt/​QtApplication.py	Exposes the application and main-window property; removes explicit subwindow parenting.
UM/​Qt/​qml/​UM/​Dialog.qml	Binds the default transient parent to the application's main window.

_{Review effort: Balanced}

[R. Burema (rburema)]

LGTM; I have a suggestion though (except I didn't test that).

[R. Burema (rburema)]

Also; I think exposing QtApplication like this could have more advantage than just in this ticket -- I remember struggling with something lately that would've benefitted from a reference to the main app. Maybe worth searching for cases like that? (Or at least keep it in mind.)

[Erwan MATHIEU (wawanbreton)]

Also; I think exposing QtApplication like this could have more advantage than just in this ticket -- I remember struggling with something lately that would've benefitted from a reference to the main app. Maybe worth searching for cases like that? (Or at least keep it in mind.)

There was a case exactly like that indeed, where we could definitely have done that... So to keep in mind indeed, however at some point Uranium will merge into Cura, and that will be obsolete...