I am finding problems with the terrain editor need help.

I just downloaded the newest version of unity for Mac and I have noticed buggy problems like the terrain editor not always wanting to work. From time to time, the brush size and Opacity size get stuck and won't let me move them to the sizes I want. This is really annoying . Does this sound like a bug of some kind? I am brand new to this and for no coding or game developing experience at all I think I am doing pretty well at learning all the tools, but it is frustrating when this happens, it makes me want to throw my computer against the wall and after restarting the program and starting all over again it finally works.... is this normal??