Misbehaving auto completion?

I run Quanta+ on a Ubuntu Feisty environment almost exclusively to edit 
HTML/PHP scripts. It works very well but there is a small annoyance: 
after some time using the auto-completion feature, it begins to try to 
complete my code with some Array::... instructions instead of PHP ones 
and processing gets quite slow.

I have been trying to understand the cause better and find a solution 
without disturbing the community but got nowhere.

Help would be appreciated.

Thanks in advance

Jose Armando Jeronymo