Description:
The spellcheck highlight (the red wiggly underline) fails to update after a word has been added to the dictionary in Impress (7.6.7.2 on Ubuntu 20.04 and 18.04). I have added multiple words to my dictionary, like "incompressible" but even other uses of the same word on the same slide remain underlined after adding the word. I have to literally edit and re-type the word to make other instances of the visually-reported error disappear.

Steps to Reproduce:
1. Open a new Impress document (Presentation)
2. In slide title, type 'adiabatically' 
3. In the slide body, type 'adiabatically' 
4. Note that both words are underlined as spelling errors.
5. Right-click on the first word and choose 'add to dictionary'

Actual Results:
What happens is that the first word loses its wiggly underline, but the second does not.

Expected Results:
Obviously adding the word to the dictionary should trigger that error to no longer be reported anywhere else in the document.


Reproducible: Always


User Profile Reset: No

Additional Info:
No other info.