One can delete songs from the library by selecting "Remove from Play Queue" from the right-click menu over the Play Queue.

To Reproduce:

1) Select a song(s) from the library
2) Right click on the Play Queue
3) In the menu, select "Remove from Play Queue"

Expected:
To do nothing if nothing is selected in the Play Queue or actually remove the song from the Play Queue.

Result:
Songs selected in the library are deleted instead.