Added white background into dtkCreator's plugin browser item view.
Added white background into dtkCreator's plugin browser item view.

d-tk/dtk,rdebroiz/dtk,NicolasSchnitzler/dtk,d-tk/dtk,rdebroiz/dtk,rdebroiz/dtk,NicolasSchnitzler/dtk,d-tk/dtk,d-tk/dtk,NicolasSchnitzler/dtk,d-tk/dtk,NicolasSchnitzler/dtk,d-tk/dtk,rdebroiz/dtk