Question

Take this little example:

h=waitbar(0,'a window')
close all

The command close all here will not close the waitbar.
To close it I must use close all hidden.

But why Matlab considers h = waitbar as an hidden handler?

Answer 1

get(h, 'HandleVisibility') tells you its handle visibility is callback, so it’s hidden when accessed from anything other than an internal callback (by MATLAB of your GUI code). close all operates only on visible handles, so your waitbar won’t close.

EDIT: Looks like you can mess with this system and set(h, 'HandleVisibility', 'on'). Now when you try close all the waitbar will disappear.