Crash when pvextracting

[keflavich]

I tried pvextraction on a particular file (ask and I'll send a link) and it crashed with this error:

Traceback (most recent call last):
  File "/Users/adam/repos/glue/glue/viewers/common/qt/mpl_widget.py", line 113, in paintEvent
    self.roi_callback(self)
  File "/Users/adam/repos/glue/glue/core/qt/roi.py", line 41, in _paint_check
    self.paint(canvas)
  File "/Users/adam/repos/glue/glue/core/qt/roi.py", line 45, in paint
    self.draw_polygon(canvas, x, y)
  File "/Users/adam/repos/glue/glue/core/qt/roi.py", line 97, in draw_polygon
    p = self.get_painter(canvas)
  File "/Users/adam/repos/glue/glue/core/qt/roi.py", line 86, in get_painter
    p.setBrush(Qt.NoBrush)
NameError: name 'Qt' is not defined
QWidget: It is dangerous to leave painters active on a widget outside of the PaintEvent
QPainter::begin: A paint device can only be painted by one painter at a time.
Segmentation fault: 11

version is glueviz==0.8.0.dev26152615

[astrofrog]

Duplicate of #892 - could you try fixing the missing import and seeing if that works? (from glue.external.qt.QtCore import Qt) - and if so can you open a PR?

[keflavich]

@astrofrog done, and it fixes the problem. I included the "closes" tags in the commit.

[astrofrog]

Thanks! I'll add a changelog entry (needs a new 0.7.1 section)