Treeview node not being highlighted during drag over v0.19

[PMac]

Dragging an item (eg a line) over a treeview group does not appear to activate the highlight on the group label text. The highlight appearing whilst dragging an item to a new treeview node is a necessary visual cue that I'm about to drop the item into the correct node.

Suspect the treeview node drag/drop events may be only partially activated, as dropping an item onto the group even when not highlighted will transfer the item into that group. Selecting the line and right-clicking Utilities/Move into Group functions correctly.

Specifically selecting the group (ie activating the mouse select events) appears to produce highlights so it seems the treeview mouse events are OK.

Have noticed this issue exists in Windows 0.19 non-Conda versions

https://github.com/FreeCAD/FreeCAD/rele ... nVS2015.7z

OS: Windows 7 SP 1 (6.1)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.16699 (Git)
Build type: Release
Branch: master
Hash: e484a52e9d4ccaa360952cd8755b4a8ee6ad2ea1
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/New Zealand (en_NZ)

but does not exist in the other Py3QT5-WinVS2015 version on offer

eg the Conda version
https://github.com/FreeCAD/FreeCAD/rele ... nVS2015.7z
(have not tried Conda 16687 version)

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.16653 (Git)
Build type: Release
Branch: master
Hash: aaae82970461c10b76281f4e4454ab086b5f7f21
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/NewZealand (en_NZ)

Have tried resetting preferences to clear config files and have been alternating between the Conda (uses earlier Python/Qt) and VS2015 (uses latest Python/Qt) 0.19 64 bit updates as they are released always with treeview highlight failure in the non-Conda version. I also notice that the Conda About FreeCAD does not pick the fact that my machine is living on borrowed time at Win 7 SP1.

Sample file attached.

Is this an issue or any suggestions that I could do at this end?