I've been playing with a Black Gambas Theme.
It's still not quite right but it's getting there.

I can't attach as a file as the extension is not allowed/recognised…
So open a text file an copy in the text below and save in your projects area as :  black.gambas.theme
[Theme]
Background="#000000"
Normal="#FFFF00"
Keyword="#007FFF,Bold"
Datatype="#4C00FF,Bold"
Function="#3398C3,Bold"
Operator="#37B5DF,Bold"
Symbol="#FFFFFF"
Number="#FFFF00,Bold"
String="#FF7F00"
Comment="#00BF00"
Help="#888786,Bold,Italic"
Preprocessor="#006E28,Bold"
Breakpoint="#FF5F5F"
Current="#42C9FF"
Selection="#CFBFFF"
Highlight="#77BF2F"
CurrentLine="#5F5F5F"
Error="#BF0303,Underline"

Load the theme in Gambas settings to try it out.
If you have made any changes to your current theme , make sure that you have saved them first.

Any suggestions welcome.

Thank you!

Here's a preview for those interested, and also I added the file for import (Tools -> Preferences -> Theme):

Here's the theme file:

(Click to enlarge)

Hi Quin, nice to hear from you again.

I tried your theme on Linux Mint 17 and 18 and for some reason I get this: -
<IMG src="http://www.cogier.com/gambas/BlackTheme.png"> </IMG>

 The theme is only for the editor, not the GUI. That's the DE's business.

Are you saying that you changed your DE settings to get the result in your post?

Yes, this is Dark Breeze theme in KDE.

 Hi Guys,
It appears I did not have any notifications turned on so did not know that someone had replied.- Fixed now.
Very glad to see a Gambas forum site up and running in English.

I've been away so long that I need to start learning again - so many changes to Gambas - it is maturing into something really formidable.

Gambas is really unique! Hoping for the best for the Purism phone, and that we can get Gambas going on that side as well    8-)

Makes it look like modern Visual Studio.

I still prefer grey myself, but then I started on Visual Basic 6 on Windows 98.