slow response and commands not executed

holding ‘shift’ and selecting more than one face, is often not recognized.
deleting objects take forever
the refreshing of the menu on the left hand side takes up to 1 second.

e.g. when I try to subtract an object from another object (see video):

  • I select the first object (0:49)
  • I click 'CTRL-B ’ and select the second object (it’s now 0:53)
  • Shapr3d understands what I’m trying to do, but the selection of the objects is lost (0:56)
  • I reselect the objects (it’s now 0:59)
  • Shapr3d confirms that I can do it, and shows the “check” button (1:01)
  • I click the “check” button (i’t’s now 1:03)
  • nothing happens…