Could anyone please tell me what "hung up" means in following paragraph?

"One of the things that some people get hung up on is the look and feel of the desktop. More precisely, some Windows users who look at Ubuntu Linux get hung up on how it doesn't look and feel like Windows"
Dear developer

The verb "to hang up" is, of course, very old and means to suspend someone or something in one place so that it cannot move (except swing slightly from side to side)

In the late 1950's it became a noun-phrase - probably introduced by psychotherapists - to mean an issue or problem that stops a person acting normally - like a rope on which they've been hung up

- I invited him to the football match but he said he had a hang-up about being in large crowds

A few years later, "hung up" became an adjectival phrase, usually with "on" or "about" - to describe a person who has a "hang-up"

- He didn't enjoy the football match - he was really hung up about the large crowd

- He keeps saying the operating system looks nothing like Windows. Personally, I can't get hung up on that

Hope this helps, Dave
Thanks Dave