I may be missing something very easy but while picking up loot and new skills, I often somehow do something where my new torghast skill disappears without being chosen and any future skills I get a message similar to “you have a skill option open, please chose one before being allowed to choose this one” In other words, I miss one, I can’t open it and can’t access future skills.
Is there an option somewhere to open up my available skill choice, the floaty white thing is gone. Thanks in advance!
It should only minimize if you click off the selection. There should be a little gray bar or animation on your screen somewhere showing that you have an anima power choice pending.
Your UI could be blocking it depending on how it is set up. Mine appears directly under where the menu for the anima powers pops up.
Edit: you can also try /reload to make the minimized icon visible again if it disappears.
Just a visual version of what Omne said:
This is the usual anima power selection. If you hit ESC or move away from the floating orb, the selection is minimized.
On this shot, on my warlock WA above the soul shards count, next to the Darkglare button, you see a grey orb (which wasn’t there on the first screenshot). Clicking on that orb will bring up the selection panel again.
Your UI might differ slightly but by default, slightly below the panel is where the orb will be if it’s minimized… just like Omne said.
Shutting it off might have been better for this screenie. Just sayin’. I know it’s visible, but having to describe exactly where one would be looking for the orb - in an enlarged screenshot of the orb - should tell ya something. 
Yes, if by “slightly” you mean there’d be nothing around the orb.