git: openjdk/jfx-sandbox: glass_gtk_bug_squashing: Fix transparent window should not have background

[duke]

Changeset: 9c72ba1d
Branch: glass_gtk_bug_squashing
Author:    Thiago Milczarek Sayao <thiago.sayao at gmail.com>
Date:      2025-04-17 11:33:11 +0000
URL:       https://git.openjdk.org/jfx-sandbox/commit/9c72ba1d96842db21d2547ca951c4c67e147689b

Fix transparent window should not have background

! modules/javafx.graphics/src/main/native-glass/gtk/glass_window.cpp
! tests/system/src/test/java/test/robot/javafx/stage/StageWhiteBackgroundTest.java