QColorDialog's Pick Screen Color Causes Memory Leak

Use of the screen color picker in QColorDialog causes memory leaks.

Steps to Replicate:

• Run attached program in debug mode (it was run in Visual Studio 2015)
• open a QColorDialog
• click "Pick Screen Color"
• cancel pick mode (eg. escape key), cancel color dialog (eg. escape key), quit application

Results:

• Console output indicates:

  Detected memory leaks!
  Dumping objects ->
  {22466} normal block at 0x0055B2F0, 12 bytes long.
   Data: <            > 01 00 00 00 FF FF FF FF CD CD CD CD 
  {22464} normal block at 0x0055CD80, 64 bytes long.
   Data: <x 9g  U       =g> 78 DC 39 67 B8 B2 55 00 00 00 00 00 20 F8 3D 67 
  {22463} normal block at 0x0055B2B8, 12 bytes long.
   Data: <d Re  U   O > 64 DC 52 65 80 CD 55 00 B0 99 4F 00 
  {16409} normal block at 0x00552180, 32 bytes long.
   Data: <                > 01 00 00 00 00 00 00 00 04 00 00 00 10 00 00 00 
  {188} normal block at 0x004E2D48, 112 bytes long.
   Data: <  ;g  N       =g> D4 E6 3B 67 08 1A 4E 00 00 00 00 00 20 F8 3D 67 
  {187} normal block at 0x004E1A08, 8 bytes long.
   Data: <  ;gH-N > E0 E6 3B 67 48 2D 4E 00 
  {186} normal block at 0x004D08C8, 64 bytes long.
   Data: <         !U   <g> 01 00 00 00 00 00 00 00 80 21 55 00 98 8F 3C 67 
  Object dump complete.
  

• Expected results: not an issue.

Note: Memory leaks are detected via a custom built Qt5Cored.dll linked with Microsoft's C-runtime library (this is the only modification to an otherwise clean Qt 5.6 build).

• If you keep calling pick screen colors, more leaks appear.
• If you select a color without calling pick screen colors, no memory leaks appear.
• Tracing through, the leak appears around the call for q_pickScreenColor(), and before the first grabScreenColor call.