[Plugin: SensitiveTagCloud] Bug when you uninstall and re-install sensitive tag cloud

Hi
thanks for your plugin, but I notice a sort of bug :
when I upgrade through my WordPress wp-admin interface to 1.3 version, the plugin disappear from my plugin list.
So, I tried to delete the files on my FTP, wordpress tell me that the files have disapeared, but when I re-install the plugin, same problem : the plugin works, but doesn’t appear in the plugin list.
Any idea? bug?
my wordpress version : 2.7

Other request: When you search an article with a word (ex: “training”), the function stc_widget() shows only the tag from the article with the word “training”
I would show as well only the category of the article containing the word “Traning” … could you create a function stc_widget_category … or something else?

regards
xavier