No compatibility modes seem to be active. Aero gets disabled during the creation of Panda3D window, not when the Python interpreter starts, so I think it’s safe to rule out compatibility mode as a cause.
When this happened to Blender, there was some discussion around the topic:
developer.blender.org/T49215
This is what Roaming Ralph outputs when notify-level-wgldisplay is set to “debug”:
Known pipe types:
wglGraphicsPipe
(all display modules loaded.)
:display:wgldisplay(debug): Preliminary pixfmt #197 = depth_bits=24 color_bits=48 red_bits=16 green_bits=16 blue_bits=16 alpha_bits=16 back_buffers=1 force_hardware
:display:wgldisplay(debug): Found 140 advanced formats: [ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 5
1 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 13
7 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 200 201 202 203 204 205 206 207 ]
:display:wgldisplay(debug): Selected advanced pixfmt #197 = depth_bits=24 color_bits=48 red_bits=16 green_bits=16 blue_bits=16 alpha_bits=16 back_buffers=1 force_hardware
:display:wgldisplay(debug): ================================
:display:wgldisplay(debug): Selected GL PixelFormat is #197, ICD driver
PFD flags: 0x0000000000000225 ( PFD_DOUBLEBUFFER| PFD_SUPPORT_OPENGL| PFD_DRAW_TO_WINDOW| PFD_SWAP_EXCHANGE|)
PFD iPixelType: PFD_TYPE_RGBA
PFD cColorBits: 64 R: 16 G: 16 B: 16
PFD cAlphaBits: 16 DepthBits: 24 StencilBits: 0 AccumBits: 0