can't show Marker Placement again after closing it

[Elaine Meng]

After I use the little "X" to close Marker Placement, I can't get it back. Choosing it from the Tools menu shows the toolshed command but nothing happens. Clicking the mouse-mode icon gives a traceback:

Traceback (most recent call last):
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/mouse_modes/tool.py", line 57, in button_press_cb
run(self.session, 'mousemode %s %s' % (button_to_bind, mname))
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/core/commands/run.py", line 31, in run
results = command.run(text, log=log)
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/core/commands/cli.py", line 2512, in run
result = ci.function(session, kw_args)
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/core/commands/mousemode.py", line 42, in mousemode
mm.bind_mouse_mode(button, modifiers, mode)
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/core/ui/mousemodes.py", line 180, in bind_mouse_mode
mode.enable()
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/markers/markers.py", line 33, in enable
p.update_settings()
File "/Users/chimera/Applications/ChimeraX_Daily.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/markers/markergui.py", line 90, in update_settings
self.mode_button.setText(self.mode_menu_names[mode])
RuntimeError: wrapped C/C++ object of type QPushButton has been deleted

[Tom Goddard]

Fixed.