After updating to DraftSight 2015 for Mac OS X, switching from one open drawing to another from the window menu doesn't work at all (the proper window doesn't come into focus). It's possible, however, to switch windows using the OS X dock. Also, closing drawings makes DraftSight sometimes crash, and sometimes get stuck since the other windows doesn't come into focus.

This problem appears on two different computers, one with OS X Yosemite and one with OS X Mavericks installed, so it's clearly a bug in the program. 

UPDATE: Reverted to an older version of Draftsight (V1R5.2) and it doesn't have this problem.