----
x
<KeyPress event state=Mod3 keysym=x keycode=88 char='x' x=1010 y=941>
<KeyRelease event state=Mod3 keysym=x keycode=88 char='x' x=1010 y=941>

Win show elaborated Win10 start menu + tiles
<KeyPress event state=Mod3|0x40000 keysym=Win_L keycode=91 x=950 y=851>
<KeyRelease event state=Mod3 keysym=Win_L keycode=91 x=1143 y=958>
I did not always see KeyRelease - maybe because followed by <Focus Out> first

Win-X show system menu
<KeyPress event state=Mod3|0x40000 keysym=Win_L keycode=91 x=806 y=846>
Definitely has different effect, raising simple menu with no time delay.
Never see keyRelease, probably because FocusOut is very quick.
The Win10 Start display with tiles is more elaborate than Win-x system menu
and Win7 start menu.

Win-x show desktop == remove all else, very quick
<KeyPress event state=Mod3|0x40000 keysym=Win_L keycode=91 x=696 y=814>
<Unmap event>
<FocusOut event>

Conclusion: Win removes focus so tk does not see followup key, nor, usually, Key-Release, so code should not look for that.

D-Win in that order
<KeyPress event state=Mod3 keysym=d keycode=68 char='d' x=707 y=939>
<KeyPress event state=Mod3|0x40000 keysym=Win_L keycode=91 x=707 y=939>
<KeyRelease event state=Mod3 keysym=d keycode=68 char='d' x=707 y=939>
<KeyRelease event state=Mod3 keysym=Win_L keycode=91 x=707 y=939>
Win ignored by system if another key down.

Cntl
<KeyPress event state=Mod3 keysym=Control_L keycode=17 x=1162 y=958>
<KeyRelease event state=Control|Mod3 keysym=Control_L keycode=17 x=1162 y=958>
x
<KeyPress event state=Mod3 keysym=x keycode=88 char='x' x=1097 y=969>
<KeyRelease event state=Mod3 keysym=x keycode=88 char='x' x=1097 y=971>
Cntl-x, definite down in that order
<KeyPress event state=Mod3 keysym=Control_L keycode=17 x=1162 y=958>
<KeyPress event state=Control|Mod3 keysym=x keycode=88 char='\x18' x=1162 y=958>
<KeyRelease event state=Control|Mod3 keysym=x keycode=88 x=1162 y=958>
<KeyRelease event state=Control|Mod3 keysym=Control_L keycode=17 x=1162 y=958>