SP2013-"Shared With" abnormality for Lists.

Question

This is an on premise SharePoint 2013 installation. I routinely customize permissions for folders created within a Document library. I also routinely customize permissions for a List as a whole.  But, I want to customize permissions for folders
I created in a List just like for folders in a Library.  The "Shared With" module fails - times out.  I can't break inheritance nor assign unique permissions to a list folder even as site owner.

Answer 1

UPDATE!
The "shared with" module perhaps in combination with other things is to blame.  It is an intermediate step to launching the advanced permissions module.  When the module fails, I can't launch manage permissions module even though I have
permissions.  I found a work-around to by-pass the "shared with" module.  
Select SITE SETTINGS gear.
Under Site Administration, select CONTENT & STRUCTURE.  
Select the applicable list from site contents to expose items of the list including any folders.
Carefully hover over a folder to activate the dropdown associated with the folder name. 
**PAYOFF** select the "MANAGE PERMISSIONS" from drop down options.  The advanced controls module launches to permit breaking inheritance and assign unique permissions.
This does not fix the "Shared With" module failure itself, but offers another route to the desired end.
Cliff