And you did set EraseBackground to false?
And activated GDI+ ? 
[quote=230709:@Eli Ott]On Windows this is not possible as long as the native win32api is used, because it is not supported by MS. There are hacks, but they are ugly, the controls are flickering when resizing the windows, etc.
By the way the Xojo label is not the native win32api control, it is a canvas which draws the string in its paint event.[/quote]
Much less hacky (no declare), for buttons, use a BevelButton placed off window, set its background to white, then DrawInto it in a picture and set that picture Transparent = True.
Place it into a label backdrop and boom, you got a transparent button.
It is not a rumor. There is a feedback request active <https://xojo.com/issue/28733> now number 6 in the top ten. At the moment I cannot recall where, but I read from Xojo that it would be easier when 64 bit is ready. Whatever that means.
Of course I would love to have more info on that as well. Although a practicing Buddhist, I am going to light some candles at the altar of Saint Isidore of Seville, in the hope he will inspire Xojo in their magnificent sollicitude to lay a benevolent eye on the poor confused Windows souls who have been banned for so many years in loveless abandon.
Ok, thanks Michel. And I begged Xojo inc. to commit more efforts in Windows developments, so who knows. 
I see the status of <https://xojo.com/issue/15940> changed from Reviewed to Implemented. So we can probably expect the change in a future version of Xojo.
Thank you Norman
Just used it today. It really is much better.
In particular, a project created on Mac will now look exactly the same. In the past, all labels turned opaque, and it was a mess having to set all of them transparent.
Congratulations and thank you !