Recently, I have been having an issue where adding a word to one of my languages' dictionary causes the web page to stop responding and my browser to slow significantly until the tab is closed. The word is added - I can confirm this by searching for it on the language's user-facing page - but I have to close the browser tab and re-enter the old version editor for the article if I want to add more. Just after adding the word, right after the browser tab starts hanging, the list of words in the left column of the dictionary tabs disappears from view.

Steps to Reproduce

It happens when I try to edit this article. The number of entries may be a factor, but I've only had performance issues on low-end machines before.   1. Go to the dictionary tab in the old version editor on a language article 2. Fill out the information boxes for a new word 3. Click "Add to Dictionary" 3a. The browser tab will hang 3b. If the tab is returned to from somewhere else (e.g. checking that the word was entered on the reader-facing page) then the dictionary list in the editor will not be visible when it is returned to

Operating System

Windows

Browser

Firefox

Related Entity

The issue is confined to the old version editor; as far as I can tell, there is not a way to edit the dictionary from the new editor. The visual effect seems to be secondary the the issue, as it only manifests if I leave the tab and come back to it.     This is moments after hitting Add to Dictionary. I added the word 'lama' to the language dictionary, but cannot add more because the browser tab has frozen and must be closed (takes longer to accomplish the longer I wait).     Despite the browser tab hanging up, the word has appeared in the dictionary. It can be edited from the reader-facing page without any apparent issues.