Description:

When using a display with scaling setting to more than 100%, floating pane docking does not work as intended. When dragging a pane out of a PaneGroup, and without releasing it, you drop it on top of another tab (so it is inserted into that position in the PaneGroup), nothing happens (window stays floating in that position). If you drag the already floating window on top of the same tab, then the default behavior happens and the pane is docked into the group. This behavior is reproducible on the Telerik UI for WPF Demo app.

See attached video for reproduction case in Demo app.

Technical Details:

For the failing scenario DragDelta on the ToolWindow is being triggered with wrongly scaled mouse position. On second drag drop operation, DragDelta receives properly scaled mouse position.

Failure case mouse positions:

DRAG START {864,128.8}
DRAG DELTA {871.2,142.4}
...
DRAG DELTA {864.8,114.4}
DRAG END {1081,143}

Second case mouse positions:

DRAG START {862.4,116}
DRAG DELTA {873.6,160.8}
...
DRAG DELTA {860.8,112}
DRAG END {860.8,112}