Damn I just bump into these things :P
Anyway I have timed this figure so it would blink images in a certain time: (btw this works fine, it's for a comparison to my faulty code)

Code:
function light_change()
{
   while(1)
   {
      //It also works whn I'd use If statements, but switch is something I don't use all the time and decided to do it here :P
      switch (active)
      { 
         case 0: //if active = 0
            if (p_tele_light.bmap == lgt_out) //Blink
            { 
            p_tele_light.bmap = lgt_red;
            }else{
            p_tele_light.bmap = lgt_out;
            }
         break;
         default: //basically if active = 1
            p_tele_light.bmap = lgt_active;
      }
   wait(-0.2); //Delay, which works!
   }
}

//this is called in main() like so:

function main()
{
   [...]
   level_load(""); // load an empty level
   wait(2);

   light_change(); //Working delay function!
   

   while(1) //that while loop
   { 
   [...] //Other stuff here... 
   }
}

So this works. But I tried to do delay similar to this and it won't work:

Code:
function shoot()
{
   while (mouse_left)
   {
      if ((gun[g_type][1] > 0)) 
      {
         [...]
      } 
   wait(-5); //Trying to delay that while, thus when holding mouse_left I'd get intervals for about 5 seconds...
   }
}


//In function main(). Well it's more difficult. If I'd place it next to my earlier light_change() it wouldn't work at all, I think it has something to do with "mouse_left detection". Engine won't update it because out of somekind update... :P

If I'd place it into main()'s "while loop", the delay won't give delay. It happens like it would be "while (1)".

Another might be that light_change() has "else statement" which makes the active variable check longer because when in 1.step "active = 0" and suddenly in that step "active = 1" then it takes one whole step to recheck that value to go into else.

I'm not sure which is the case. I have tested it in many ways.
How to work around it? How to get that delay with mouse_left == 1..

Hope I have given enough info...

LiteC Free btw.

New into Gamestudio and eager to learn it..
Stuff and games done in 2D: LINK