See whether the user has dbl-clicked btn 1...

comments are in the source.
basically define the globals and constants and the isDoubleClick() function
set sensitivity to your taste. call function from within your main loop.

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    `***************************************************
` mouse double-click detection code
`***************************************************
` courtesy of skyser from Electric Funstuff
` http://www.electricfunstuff.com
` if you use this code in a real product please give EFS
` a shout out somewhere. thx!
`***************************************************


`for our purposes here we use this definition...
`  a dbl-click = a press/release/press of mouse button 1
`  within the specified interval

` you need to define these vars
GLOBAL clickStartTime = -1
GLOBAL inClickCycle = 0
GLOBAL isBtnDown = 0

`sensitivity in milliseconds - adjust this to taste
`lower for less sensitive, higher for more
#CONSTANT DBL_CLICK_INTERVAL 350


GLOBAL dblClkCount = 0   ` for testing purposes




do
   cls
   if isDoubleClick() = 1 then inc dblClickCount
   if escapekey()=1 then exit

   text 10,10,"dbl click count: " + str$(dblClickCount)

loop
end


` call this from your own code in your main loop
` func returns 1 if a dbl click happened, 0 otherwise
function isDoubleClick()
    curClickTime = TIMER()
    clickCode = mouseclick()

    `if no click and not in cycle then exit
     if (clickCode <> 1) AND (inClickCycle=0) then exitfunction 0

     select clickCode
        case 0:   `no buttons down
            `if in cycle and btn was down, then release
            if (inClickCycle = 1) AND (isBtnDown = 1)
                isBtnDown = 0
            endif : endcase     `ignore no btns if not in cycle
        case 1:   `left button down
            if inClickCycle=0 `not in cycle, so start new cycle
                clickStartTime = curClickTime
                inClickCycle = 1
                isBtnDown = 1
                exitfunction 0
            else
                `we're in a click cycle and the button is down
                if isBtnDown = 1 then exitfunction 0  `ignore if already down

                `so we know now btn is not down, so this is a new click in the cycle
                `therefore it's a potential dbl-click

                elapsedTime = curClickTime - clickStartTime

                `reset the cycle
                inClickCycle = 0

                `if this all happened within the right time span then
                `call it a dbl click
                if elapsedTime <= DBL_CLICK_INTERVAL
                    exitfunction 1
                endif
            endif : endcase
     endselect
endfunction 0