[Can't switch tools using hotkeys after clicking on any window besides the main one.]

I shouldn't, but sometimes I have to. I'm not sure what causes it; I just launched pdn again to test it and just hovering over the main window works, but last night when I was working on some things then I definitely needed to click on the window every time. I had it open for a while and had several images open at the same time when I noticed that bug.

[Can't switch tools using hotkeys after clicking on any window besides the main one.]

See title. After clicking any of the secondary windows - colors, layers, etc. - then I can't use hotkeys to switch tools until I click on the main window again. This is incredibly annoying, as I usually accidentally use a tool I wasn't intending to, so I either have to ctrl+z or click on the header of the main window every single time I want to switch a layer or adjust colors.

 

I don't know if this is exclusive to my computer, so here's the diagnostics log just in case:

Spoiler

Application    paint.net 4.0.19 (Final 4.19.6484.39094)
Build Date    Monday, October 2, 2017
Install type    Classic
    
Hardware accelerated rendering (GPU)    False
Animations    True
DPI    96.00 (1.00x scale)
Language    en-US
    
OS    Windows 10 x64 (10.0.15063.0)
.NET Runtime    4.0.30319.42000
Physical Memory    8,091 MB
    
CPU    Intel(R) Core(TM) i5-4690K CPU @ 3.50GHz
    Speed    ~3492 MHz
    Cores / Threads    4 / 4
    Features    DEP, SSE, SSE2, SSE3, SSSE3, SSE4_1, SSE4_2, XSAVE
    
Video Card    AMD Radeon (TM) R9 390 Series
    Dedicated Video RAM    8,169 MB
    Dedicated System RAM    0 MB
    Shared System RAM    4,045 MB
    Vendor ID    0x1002
    Device ID    0x67B1
    Subsystem ID    0x2358148C
    Revision    128
    LUID    0x00009780
    Flags    None
    Outputs    1
    
Video Card    Intel(R) HD Graphics 4600
    Dedicated Video RAM    112 MB
    Dedicated System RAM    0 MB
    Shared System RAM    2,048 MB
    Vendor ID    0x8086
    Device ID    0x0412
    Subsystem ID    0xD0001458
    Revision    6
    LUID    0x0000A037
    Flags    None
    Outputs    0
    
Video Card    Microsoft Basic Render Driver
    Dedicated Video RAM    0 MB
    Dedicated System RAM    0 MB
    Shared System RAM    4,045 MB
    Vendor ID    0x1414
    Device ID    0x008C
    Subsystem ID    0x00000000
    Revision    0
    LUID    0x0000A00B
    Flags    Software
    Outputs    0