Are there any error messages displayed in the browser's console when this happens?

• Firefox ≥24
• Internet Explorer
• Google Chrome
• Apple Safari
• Opera

(I originally filed this bug on en-Wiki)
No console message is displayed, when I save the article (Windows XP, FF 38). But when I started the editing session with VE earlier, and it was loading the article ("Hockenheim" on en-Wiki), I noticed the following error in FF console:

"Exception in store-localstorage-update:" load.php:177:752
"NS_ERROR_DOM_QUOTA_REACHED: Persistent storage maximum size reached" DOMException [NS_ERROR_DOM_QUOTA_REACHED: "Persistent storage maximum size reached"
code: 1014
nsresult: 0x805303f6
location: https://en.wikipedia.org/w/load.php?debug=false&lang=en&modules=jquery%2Cmediawiki&only=scripts&skin=vector&version=XAzQDrxo:175]

It may be only a local problem on my (old) PC, but thought I'd mention it.

Confirmed in Firefox 38, Ubuntu.
There are no relevant messages in webconsole. (@GermanJoe: Just FYI: that "localstorage" exception is related to ResourceLoader in Firefox, and will appear on every page. It's being worked on, but is unrelated to this. :) )

The Gadget only loads on 'document ready'. It's thus not compatible with VE, since VE redraws the categories. This should be fixed, by introducing hooks for these page sections like described in T53583, and then patching both Visual Editor and HotCat to make use of those hooks.

From the Community Tech sprint kick-off meeting:
Support: Medium/Low (compared to other AOI tasks)
Feasibility: Medium
Impact: Low (users can always reload the page to work around the bug)
Risk: Medium (anything involving VisualEditor has some risk involved)

Priority: Low

May be able to use the following hook:

mw.hook( 'postEdit' ).add(

// reload HotCat

);

Keep in mind this is also fired after a save in the WikiText editor, so we should be careful not to load 2 HotCat interfaces.

I can get HotCat to reload when the postedit hook fires by adding the following into HotCat:

mw.hook( 'postEdit' ).add( function () { initialized = false; HotCat.started = false; run(); } );

However, when HotCat reloads after VE has recreated the page, it doesn't actually add the HotCat interface to the categories. Either something must be different about the page or there's a timing issue. Will require more investigation.

ehm, but postEdit is not the appropriate hook of course.
I'm not really in favor af abusing hooks for purposes that they were not intended for...

ehm, but postEdit is not the appropriate hook of course.

Why is postEdit not appropriate, and what would be a better hook to use?

Switched HotCat to use wikipage.content hook instead (which works for null edits as well):
https://commons.wikimedia.org/w/index.php?title=MediaWiki:Gadget-HotCat.js&diff=prev&oldid=190032143

@kaldari It seems your previous fix was the better one as you said:

In T103285#1572657, @kaldari wrote:

Risk: Medium (anything involving VisualEditor has some risk involved)

Now there are direct related bugs through this fix: T151056 T170748 and probably T147197 too.