Tab docking indicators missing (Cannot split-screen / only center dropzone visible)

Hi Devolutions Team,
I am experiencing an issue with the tab docking system in Remote Desktop Manager. I can no longer split my screen horizontally or vertically by dragging terminal tabs.
When I click and drag a tab, the 4-sided directional docking cross (top, bottom, left, right indicators) is completely missing. Only the single "center" dropzone (used to merge tabs) is visible.
Steps I have already tried (which did NOT resolve the issue):

1. Used Window -> Reset layout.
2. Closed RDM, went to %localappdata%\Devolutions\RemoteDesktopManager, and deleted all .lyt layout files along with the RemoteDesktopManager.ext file to force an interface reset.

The problem still persists after a fresh launch.

My Environment:

• Remote Desktop Manager 2026.3.12.0 64-bit (JIT)
• Runtime: .NET 10.0.12
• Platform: Microsoft Windows 10.0.26200
• Workspace: Laptop
• Allocated memory: 385 MB

Was running fine before upgrading to 2026-3.12

Could you please advise if this is a known bug in this specific release, or if there is another configuration folder I need to purge to restore the full docking indicators?
Thank you!