Window created with Windows API is not visible

[solidstate1991]

Code:

https://github.com/ZILtoid1991/iota/blob/main/inputtest/app.d

https://github.com/ZILtoid1991/iota/blob/main/source/iota/window/base.d#L104

Second one contains the constructor that should make the window 
without any issues.

When I try to create a window for testing purposes, I get nothing 
besides of an icon on the taskbar. Once I was able to get a quite 
broken window to show up, then it doesn't showed up anymore. 
Calling the API function `IsWindowVisible` returns true.