[GTK4] Missing x,y values for MouseUp event, Snippet62

[Theo-Dann-Muirhead-Renesas]

Issue was a part of #344 but has a different root cause so I'm separating it.

Running Snippet 62 with GTK4 and clicking on it outputs Down/Up events. The Down events have associated x and y values which are missing for the Up events. This behaviour does not happen with GTK3.

Head of SWT, Ubuntu 24.04.2 LTS, GTK 4.14.2

[akurtakov]

Close as PR was merged.