Paint issues

*ArmorPaint 1.0 alpha-8d9efaa, Windows*

**Issue description:**
Using Armourpaint for months designing liveries for cars in ACC. Last update hasn't been kind to me, or maybe I'm just stupid.
When I'm trying to use the paint tool in UV Island mode, it appears there is a "secret" spot within the section I'm working on that I have to click before it will actually work.
Also when using solid colour pngs, in the previous versions the shape would not increase or decrease in size along with the camera zooming in and out and the shapes seems to only hug to the extremities of the car/object. Before I could hold the shape and only use a small part of it on the car but now it's all or nothing.
I hope I have made these two issues clear.
Otherwise if there's something I've missed please let me know

**Steps to reproduce:**

https://youtu.be/smYktwoc870
https://youtu.be/GuuvlBqTKRw

Start by watching the two linked reproduction videos and comparing the paint tool's UV Island mode with solid-colour PNG behavior in ArmorPaint 1.0 alpha-8d9efaa on Windows. Trace the relevant painting and brush-size behavior from the observed reproduction steps; done means both reported regressions are reproducible, addressed, and no longer occur.

Written by the indexing model from the issue text.