Suggestion: Make moving objects transparent during moving

[PinkBlender]

Hello,

Current situation / Problem*:
- Draft Workbench -> Move object
- The moving object might hinder the view to the point the user want to click.

Suggestion:
- Draft Workbench -> Move object
- while the object is being moved, it should be about 50% transparent.


*Problem found in freeCAD
OS: Ubuntu 18.04.2 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15816 (Git) AppImage
Build type: Release
Branch: master
Hash: 7ee0e4d43909ec688299b8498b240cccf8362c47
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)