Disable Fn+F4 with AutoHotKey using time - keyboard-shortcuts

Question

I want to use AutoHotKey to disable Alt+F4 when they are pressed within 0.05 seconds of each other. Otherwise, I'd like it to work as normal.
Explanation:
My Lenovo Yoga 2 Pro has alternate functions for the function keys.
For example: "F3" is mapped to volume+, "F4" is mapped to "close active window"
There are two modes:
Old-school mode: F3 just acts as F3, and you must hold Fn+F3 key to activate volume+
New-school mode: Pressing F3 activates volume+, and Fn+F3 will do the normal F3.
In either mode, I run the risk of closing my active window when I go to use volume+ because they are too close, which is very problematic. Note that AutoHotKey cannot detect the Fn key, thus I cannot use that to solve my issue.
The image below shows the AutoHotKey Key History tool. In New-school mode, I typed "asdf" and then pressed "F4" which is "close active window". You can see this actually simulates ALT+F4, and there is a very short duration between ALT and F4...
I'm thinking that I could disable this "close active window" function by having AutoHotKey interrupt an ALT+F4 combo when there is less than 0.05 seconds between the two keys. Can this be done?
Edit:
In response to Blauhirn's code, here is the original, edited for a shorter wait duration, (from 50 to 10). It works most of the time, though 1/10 times the window is still cosed:
~alt::
hotkey, alt, off
hotkey, !F4, doNothing, on
sleep, 10
hotkey, !F4, doNothing, off
while(getKeyState("alt"))
sleep, 1
hotkey, alt, on
return
doNothing:
return
Here is a change I thought would fix my focus issue by sending a 2nd Alt when the "close active window" was detected:
doNothing:
send {LAlt}
return
However, the 2nd Alt is not sent. It IS sent when the delay is above 40ish, however I find that is way too long, and in turn it interferes with my manual use of Alt+F4.

Answer 1

Have you tried using simply
F4::return
? Maybe this will override the Lenovo action for F4
Other than that, here are the two approaches I can think of:
Disabling the ALT+F4 standard win hotkey by default. Adding a custom hotkey for a delayed F4
!F4:: ; by default:
doNothing: ; this is a label (see GoSub)
return ; == do nothing
~alt:: ; alt was pressed
sleep, 50 ; wait 50 milliseconds
if(!getKeyState("alt")) ; if alt is NOT pressed down anymore, exit
return
else ; (else is actually unnecessary here)
hotkey, !F4, close ; Add new AltF4-hotkey
return
close:
winclose, A ; close the Active window
return
~alt up:: ; alt is being released
hotkey, !F4, doNothing ; remove the new AltF4 hotkey and go back to custom standard behaviour: do nothing.
return
it still triggers Alt, which usually leaves me in the menu of the active window (File, Edit, View, etc), or if typing within a textarea (such is this), it will remove typing focus.
well yes. If you decide to keep the lenovo keys, I don't think there is a way to prevent it. As you suggested, sending ALT again should solve the problem
using Input, after ALT has been pressed. Input blocks user input for a configurable time, as long as the V option is used.
(3. disabling your Lenovo Yoga 2 Pro special keys. If you need the F3 function, you can do that in AutoHotkey e.g. using send {volume_up}