4.53 vs 4.6?

[Freakish]

I have been using 4.53 with DX10 to good effect.

4.6 apparently removed the "-direct3d" switch used when configuring the libraries on Windows.

I'm wondering if it's then impossible to continue to use Qt for my Windows programming?
Can anyone tell me what the "-direct3d" switch was doing internally behind the scenes, and if it's possible to now manually do this?

I now have fighting between my MainWindow (grey) and my DX10 screen (black) so it constantly flickers.

Any help on this issue would be appreciated.