UI Layout: Properties Pane dropdown menu anomalies regarding height and alignment when pane width is extended

[rakunavi]

Hello all,

I would like to report a UI layout anomaly in the Properties Pane, specifically regarding the dropdown menu rendering logic when the pane's width is extended (such as when docked at the bottom, or manually stretched when docked on the right side).

[Observed Behavior]
When clicking a selectable property item under these extended width conditions, the dropdown list fails to render properly. Both horizontal and vertical scrollbars appear unnecessarily, and its layout alignment shifts strangely (*).
(*) Note: This applies to PCs equipped with a stylus where the Windows "Choose which hand you write with" setting is set to “Right.”

• figure1.png
  
  
  stylus_settings.png

Through detailed verification, two distinct, consistent patterns were identified:

1. Height Clipping (The "N-1" Pattern):
The visible area of the dropdown list is strictly limited to exactly "N-1" items, where N represents the total number of items in the list:

• Total 2 items: Only 1 item is fully visible (the 2nd item is cut off).
• Total 3 items: Only 2 items are fully visible (the 3rd item is cut off).
• Total 4 items: Only 3 items are fully visible (the 4th item is cut off).
• 　　　　　　　・・・

This forces the user to utilize the mouse wheel or scroll arrows despite having ample screen space.

2. Horizontal Alignment Inversion (System Handedness Dependency):
The direction of the layout shift depends strictly on the Windows "Choose which hand you write with" setting (MenuDropAlignment):

• "Left": The dropdown appears on the left.
• "Right": The dropdown erroneously shifts to the right.

The color palette popup also exhibits this unnatural, setting-dependent shift.

• figure2.png

Please note that the Windows “Choose which hand you write with” setting is available only on PCs equipped with a stylus, so the issue mentioned in point 2 can be observed only on such PCs.


[Technical Inference]
This behavior mirrors RT#7741, where the rendering engine misinterprets the Handedness flag, incorrectly applying it to mouse interactions instead of just stylus input.

• RT#7741: Bug: Touch device: Menu's always expand left, even with mouse control
  viewtopic.php?t=48922

The attached video demonstrates these behaviors, including the change in alignment when switching the system setting.

• Animation.gif

Hoping that the above information will be of some help to you.
Thank you for your hard work on this great software.

Best regards,
rakunavi

- PDF-XChange Editor PRO Version: 11.0.1
- OS Version: Windows 11 Pro / Home 25H2 Build 26200.8875
- PC Model: GMKtec Nucbox M7 Pro with HUION Kamvas Pro 19 / Lenovo IdeaPad C340-15IWL

[Daniel - PDF-XChange]

Hello, rakunavi

Thank you for the report. I have raised this with the dev team for review,

Kind regards,