Here is another bug...

I need to update a file and replace instruments. When I select them in wire frame or plot or any view for that matter and drag a new fixture from the library over them, I no longer get the blue highlight to just drop a new fixture and replace all existing fixtures. It will only let me place a new fixture. Has something changed? I am finding a lot of "bugs" in the new 2019. Can someone help here.

MacBook Pro; 2.6GHz Intel Core i76; 32 GB 2400 MHz DDR4; Radeon Pro 560X 4GB; MacOS Mojave V. 10.14.4