issues - find dimensions
if there is no dataset and 'find dimensions' is pressed on the 'dimension definition' then this will raise the following error:
Traceback (most recent call last):
File "/usr/local/lib/python3.8/dist-packages/darfix/gui/dimensionsWidget.py", line 256, in _find_dimensions
self.dataset.find_dimensions(self.metadata_type, self.tolerance)
AttributeError: 'NoneType' object has no attribute 'find_dimensions'
-------------------------------------------------------------------------------