Brush preview only works after changing the brush or save and reload

[MathemanFlo]

ArmorPaint version:
ArmorPaint.org - v0.8 (2021-08-04) - 7bf061a

OS/device including version:
Win10 x64

Steps to reproduce:

1. Create a new brush by clicking on the "New" button and get
   

2. Hover the newly created brush and wait for a preview

3. Nothing will happen

Now there a two ways to resolve the problem

1. Save and reload the project. The brush icon changes
   
   and a preview is available
2. Edit the brush. The icon gets updated immediately and a preview becomes available, too.

[MathemanFlo]

I also wanted to mention that there are these thin grey stripes between the icons.

They go away if the icon is updated but newly created brushes have one on the left side

[luboslenco]

Should be resolved via 8b43e2f, thanks for report.