Well done Andrew - I love the way you implemented the idea. This new feature will help us a lot in mastering a block! Thank you!
Fading entities which are not part of the Working Set is very helpful. Unfortunately the fade works not on solid hatches inclusive dim arrows. Would be nice if that could be fixed for the final release.
Note:
1.
Depending on the used color it can be difficult to see/read entities. In my case I used a color (green) for DIM's which is next to invisible in an "Edit Block In-place" mode. As you know you used a similar "problematic" color (blu) in your Example drawings - it disappears too.

Would it be possible to have a setting to adjust the fade grade individuality?
2.
After adding an entity to a workset QCAD fails to update the Auto Zoom function for "Edit Block". If the new entity is far away from the main block entities Autozoom will not show the whole block. You have manually to use Autozoom to see the whole content of the block which is confusing. Any chance to get the Autozoom functionality back for "Edit Block"?