[Lazarus] Dropdown File list in Source Editor

[Marco van de Voort]

In our previous episode, Graeme Geldenhuys said:
> > IMO Delphi and all other platform-specific applications and IDEs use native
> > controls.
> 
> Wishful thinking - they don't! 

They usually do, but not always :-)

Moreover, you have a choice to do so in cases where it is important  to use the less optimal one over the ownerdrawn
one. (e.g. to achieve maximal RDP speed)