Morph pause button does not work sometimes

[goddard@…]

The following bug report has been submitted:
Platform:        Darwin-18.7.0-x86_64-i386-64bit
ChimeraX Version: 0.91 (2019-08-02)
Description
The pause button usually does not work when playing a morph with the gui slider if the updating is very slow, such as when there is a surface on the morphed structure that is recomputing.

This only happens on Mac.  On Windows the pause button always works.

Debugging shows the pause button gets a MouseButtonPress event but does not get a MouseButtonRelease event on the Mac, and so the QPushButton clicked signal is not fired.

Log:
UCSF ChimeraX version: 0.91 (2019-08-02)  
© 2016-2019 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open 2h3a format mmCIF fromDatabase pdb

Summary of feedback from opening 2h3a fetched from pdb  
---  
warnings | Atom HO5' is not in the residue template for DA #173 in chain C  
Atom HO5' is not in the residue template for DT #186 in chain D  
Atom H1 is not in the residue template for MET #1 in chain A  
Atom H1 is not in the residue template for MET #101 in chain B  
  
2h3a title:  
Structural basis for nucleic acid and toxin recognition of the bacterial
antitoxin CcdA [more info...]  
  
Chain information for 2h3a  
---  
Chain | Description  
1.1/A 1.2/A 1.3/A 1.4/A 1.5/A 1.6/A 1.7/A 1.8/A 1.9/A 1.10/A 1.11/A 1.12/A
1.13/A 1.14/A 1.15/A 1.16/A 1.17/A 1.18/A 1.19/A 1.20/A 1.1/B 1.2/B 1.3/B
1.4/B 1.5/B 1.6/B 1.7/B 1.8/B 1.9/B 1.10/B 1.11/B 1.12/B 1.13/B 1.14/B 1.15/B
1.16/B 1.17/B 1.18/B 1.19/B 1.20/B | CcdA  
1.1/C 1.2/C 1.3/C 1.4/C 1.5/C 1.6/C 1.7/C 1.8/C 1.9/C 1.10/C 1.11/C 1.12/C
1.13/C 1.14/C 1.15/C 1.16/C 1.17/C 1.18/C 1.19/C 1.20/C |
5'-D(P*ap*TP*ap*TP*GP*TP*ap*TP*ap*CP*CP*CP*G)-3'  
1.1/D 1.2/D 1.3/D 1.4/D 1.5/D 1.6/D 1.7/D 1.8/D 1.9/D 1.10/D 1.11/D 1.12/D
1.13/D 1.14/D 1.15/D 1.16/D 1.17/D 1.18/D 1.19/D 1.20/D |
5'-D(P*TP*CP*GP*GP*GP*TP*ap*TP*ap*CP*ap*TP*A)-3'  
  
  

> morph #1.1-2

Computed 21 frame morph #2  

> coordset #2 1,21

> surface #2




OpenGL version: 4.1 ATI-2.11.20
OpenGL renderer: AMD Radeon Pro 580 OpenGL Engine
OpenGL vendor: ATI Technologies Inc.

[Tom Goddard]

Fiixed.

This is a Qt bug. But I worked around it by having the play/pause callback use the "pressed" signal instead of the "clicked" signal.