No Scrollbar for Virtual Scrolling and MasterDetailLayout

Engines Tree Engine
1

Hallo,

I use the TreeEngine in a MasterDetailLayout (so the tree will be shown in the main part). When I now switch on the virtual scrolling in the tree model, I get the problem, that the scrollbar disappears when ever the detail view opens.
Does anyone else had this problem before and know how to solve it?

Thanks in advance

Best regards

2

Hi @nora-azure-stem

Can you confirm which browser you are using?

Certain combinations or operating systems and browsers can lead to scrollbars being hidden by the browser. See https://connect.mozilla.org/t5/discussions/firefox-window-scroll-bar-under-windows-11-too-narrow/m-p/53580

3

Hi @malcolm-silver-ice

I’m using Firefox and I’m aware of this behaviour.
The thing is, that it works, if you don’t have virtual scroll on and the scrollbar is not just hidden (and can be make visible again, if hovering over the specific space):

Screenshot 2026-09-21 153607
Screenshot 2026-09-21 153607448×229 433 Bytes

EDIT: After testing a little bit more, it seams, that this happens not always but especially if the mouse stays over the tree row and the border is displayed while the details view is opening.

4

This reproduces. On 2026.06-ext1, with enableVirtualScroll set in the Tree
Model and the Tree Engine used as the master view of a MasterDetail layout,
the vertical scrollbar disappears as soon as the detail view opens. In my
reproduction the column layout breaks at the same moment.

I have reported this to the A12 team together with a minimal workspace.