I wanted to make the slider intuitive and easy to use. I did a little research and liked the format of the slider in Borderlands 2. It was clean, concise, and smooth. A smooth and natural slider was my main goal. I don't like having to press left or right arrows in order to raise or lower a setting so it's one of the things I wanted to avoid. The rest of this menu will also be smooth as clunky options are my worst enemy.
Problems and Solutions
I originally had a problem where the slider wouldn't recognize mouse over. Without mouse over, I couldn't move the Highlight Image. I tried to put a border around it because border's can check Mouse Over. But I didn't like that I needed one for Mouse Over and Mouse Exit. I tried a button behind the slider but that was deselected when you would interact with the slider. I ended up settling with a button over the slider that tells the slider what to do.
The next problem I had was legibility. I didn't like how the previous highlight trailed off and left the slider number alone in the vast white space. So I made a new highlight. This one has clearer edges but I'm still not 100% sold on how it looks. I might go back and revisit it.
HIDING THE MOUSE
The last, and most recent, problem I was facing was hiding the mouse when you press down. I wanted the mouse to go away so the slider handle doesn't look so offset. I've been researching high and low but can't find anything on it. It might be a bug or just that I'm still running in editor. Not sure.