Hank and I have been spent some time trying to find a direct way to reproduce the issue, but it turns out to be hard.
I could get it a couple of times by insistence - selecting loops (L) like a crazy until the keyboard stops to respond.
What I can confirm is that the issue is related to the Geometry window lost the focus and never get it back.
To try to see where the code was running in that moment I printed out the stack trace and here is the result:
Code:
Erlang/OTP 20 [erts-9.3] [64-bit] [smp:1:1] [ds:1:1:10] [async-threads:10]
Eshell V9.3 (abort with ^G)
1> wings-2.1.7.28.gdc31
Reading preferences from: c:/Users/micheus/AppData/Roaming/Wings3D/Preferences.txt
Grabbed focus lost: {wx_ref,555,wxGLCanvas,[]} geom
Stack trace: [{wings_util,'-array_greatest_key/1-fun-0-',3,
[{file,"f:/unixlike/src/wings/src/wings_util.erl"},
{line,170}]},
{array,sparse_foldr_3,6,[{file,"array.erl"},{line,1848}]},
{array,sparse_foldr_2,8,[{file,"array.erl"},{line,1837}]},
{wings_util,array_greatest_key,1,
[{file,"f:/unixlike/src/wings/src/wings_util.erl"},
{line,170}]},
{wings_we,update_id_bounds,1,
[{file,"f:/unixlike/src/wings/src/wings_we.erl"},
{line,806}]},
{wings_ff_wings,renumber,5,
[{file,"f:/unixlike/src/wings/src/wings_ff_wings.erl"},
{line,1314}]},
{wings_ff_wings,export,2,
[{file,"f:/unixlike/src/wings/src/wings_ff_wings.erl"},
{line,1251}]},
{wings_file,autosave,1,
[{file,"f:/unixlike/src/wings/src/wings_file.erl"},
{line,616}]},
{wings_file,autosave_event,3,
[{file,"f:/unixlike/src/wings/src/wings_file.erl"},
{line,595}]},
{wings_wm,handle_event,3,
[{file,"f:/unixlike/src/wings/src/wings_wm.erl"},
{line,973}]},
{wings_wm,send_event,2,
[{file,"f:/unixlike/src/wings/src/wings_wm.erl"},
{line,949}]},
{wings_wm,do_dispatch,2,
[{file,"f:/unixlike/src/wings/src/wings_wm.erl"},
{line,841}]},
{wings_wm,dispatch_event,1,
[{file,"f:/unixlike/src/wings/src/wings_wm.erl"},
{line,748}]},
{wings_wm,get_and_dispatch,0,
[{file,"f:/unixlike/src/wings/src/wings_wm.erl"},
{line,651}]},
{wings,init_part2,2,
[{file,"f:/unixlike/src/wings/src/wings.erl"},
{line,104}]},
{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,247}]}]
All the time I could repeat the issue it the stack trace was the same, so I did the autosave time shorter (2min) and the keyboard stopped to respond at that time.
If I'm not selecting anything in that moment then - after autosave has been ran - then the keyboard continues to respond.
I hope this can help us to find a fix for this issue.