A BUG: the list of personas does not show up sometimes. Puntuado con 5 de 5 estrellas

(I have customized Firefox to have the menu options displayed)
Sometimes, when I do Tools, Personas, the list of available personas does not show up. And at other times, it shows up!

I do have many tabs opened and I do not know if it causes problems with this addon but I also have 8 GB of RAM and not even half of it is used.
Therefore, I have to assume that this BUG is directly linked to this addon.

Esta valoración es de una versión anterior del complemento (1.12.1-signed.1-signed).  Este usuario tiene 8 valoraciones anteriores de este complemento.

I have had the same experience, but I haven't been able to replicate the circumstances well enough to find whether the issue is in my addon or in Firefox itself. There does seem to be a combination of the number of open windows and tabs, and the content of the tabs, that causes the issue. If anyone can find a combination that always creates the problem, I'd love to hear about it. Thanks!