Replacing a Widget and then reusing it's name for another widget will cause a crash

The user named a border "background" then replaced it with a canvas panel. After this they made an image and named it "background" and this cause a crash. Some kind of naming conflict.

1. Open the editor
2. Create a new widget blueprint
3. Add a Border Widget (from Common) to the [Canvas Panel]
4. Rename the border to "Background"
5. Right click Background in Hierarchy and choose "Replace with Canvas Panel"
6. Add an Image Widget (from Common) to the original [Canvas Panel]
7. Rename the image to "Background" (notice there is no error saying that Background is already taken)
8. Notice that the project Crashes

[Bug] Crash on widget box Replace

[4.7.6] UMG Widget Replace Crash

[4.7.6] UMG Widget Replace Crash