ID 372555 - Enabling Lock Thumb Dragging stops drawing maximize/minimize arrow icon in 3d views

Problem summary
3D viewports minimize/maximize arrows disappear when selected if 'Lock Thumb Dragging' is enabled.

Customer reported version
modo.15.2v2

Customer reported platform
windows10

Steps to reproduce

1) Launch Modo.

2) Go to Layout > Lock Thumb Dragging.

3) In the 3D viewport click on the maximize/minimize arrows in the upper right-hand corner.

4) Note that now those arrows have disappeared.

Expected behaviour
The maximize/minimize arrows should remain available.

Actual behaviour
After Lock Thumb Dragging is enabled the maximize/minimize arrows disappear.

Workaround
Unknown. 

Reproduced by support

This bug has been reproduced in:
15.2v2 - Windows 10

15.1v1 - Windows 10

15.0v1 - Windows 10

14.2v1 - Windows 10

14.1v1 - Windows 10

14.0v1 - Windows 10

13.0v1 - Windows 10

12.2v2 - Windows 10

Earliest version tested
This issue appears to be in all versions of the product