The problem persists after quite a few reboots; see previous post for workaround.
Diagnostics:
Application paint.net 4.0.3 (Final 4.3.5316.40022)
Build Date Tuesday, July 22, 2014
Hardware accelerated rendering (GPU) True
Animations True
DPI 96.00 (1.00x scale)
Language en-US
OS Windows 7 Service Pack 1 (6.1.7601.65536)
.NET Runtime 4.0.30319.18444
Physical Memory 8,191 MB
CPU Intel(R) Core(TM)2 Quad CPU Q9650 @ 3.00GHz
Architecture x64 (64-bit)
Process Mode 64-bit
Speed ~3005 MHz
Cores / Threads 4
Features DEP, SSE, SSE2, SSE3, SSSE3, SSE4_1, XSAVE
Video Card AMD Radeon HD 6700 Series
Dedicated Video RAM 1,013 MB
Dedicated System RAM 0 MB
Shared System RAM 3,839 MB
Vendor ID 0x1002
Device ID 0x68BA
Subsystem ID 0xE144174B
Revision 0
LUID 0x0000C456
Flags None
Outputs 2
Interesting question "what language". I use Dragon NaturallySpeaking Professional's scripting language to control almost all aspects of my computer interaction. I have medical issues which limit (but not preclude) the use of keyboard & mouse. To be on the safe side, before posting originally, I made sure to try direct keyboard input completely bypassing any scripting, the results were the same in either case.