Pleased you are back to normality.
Quote:
..I am puzzled as to why the default value of the brush is 2. 050 and Dynamics is set to Pressure Opacity...
That is strange but set it up whatever way you want then go and save the tool options and save the window positions.
This is my starting position, PClinuxOS and Gimp 2.8.14
A brush rather than air-brush and the brush shape is not a standard Gimp brush. Set to size 3 and spacing 28
The dynamics is a local dynamics file but is empty. It is there for whatever I want to apply.
Dialogs, the obvious layers and brushes but if you want something else set it up and then save the settings.