Blocks become slightly transparent when dragged

Expected Behavior

When dragging blocks their visual appearance should not change.

Actual Behavior

As soon as you drag a block (from the toolbox or the workspace) it gets slightly transparent.

Steps to Reproduce

Fire up the vertical playground and drag some blocks around. Notice they are slightly transparent. It is easiest to notice this when dragging over some features... like the toolbox seam or other blocks.

Operating System and Browser

All

Notes

I believe this change came in through the large Blockly update... and it seems Blockly has this behavior, so I do understand it might be intentional... but as Scratch doesn't work like this... nor did scratch-blocks previously, I'm wondering if its a bug or a feature. Maybe ideally this could be a configuration setting.