Another approach would be to give a button the multiline button style in the initialization section of the a dialog callback:
#DefineSubroutine MLButtonProc(MLButton_Handle,MLButton_Event,MLButton_Name,MLButton_EventInfo,MLButton_ChangeInfo)
switch MLButton_Event ; Switch based on Dialog Message type
case @deInit ; Standard Initialization message
BS_MULTILINE = 8192
BS_CHECKBOX = 2
hControl = DialogControlGet(MLButton_Handle, "PushButton_OK", @dchWnd)
hUser32 = DllLoad("User32.dll")
CtrlStyle = DllCall(hUser32, long:"GetWindowLongW", long:hControl, long:-16)
DllCall(hUser32, long:"SetWindowLongW", long:hControl, long:-16, long:(CtrlStyle&(~BS_CHECKBOX))^BS_MULTILINE)
DllFree(hUser32)
DialogControlSet(MLButton_Handle, "PushButton_OK", @dcTitle, "Line one":@CRLF:"Line Two")
return(@retDefault)
endswitch
return(@retDefault)
#EndSubroutine ; End of Dialog Callback MLButtonCallbackProc
MLButtonFormat=`WWWDLGED,6.2`
MLButtonCaption=`Multiline Button Example`
MLButtonX=081
MLButtonY=099
MLButtonWidth=408
MLButtonHeight=166
MLButtonNumControls=002
MLButtonProcedure=`MLButtonProc`
MLButtonFont=`DEFAULT`
MLButtonTextColor=`DEFAULT`
MLButtonBackground=`DEFAULT,DEFAULT`
MLButtonConfig=0
MLButton001=`111,111,068,048,CHECKBOX,"PushButton_OK",DEFAULT,"OK",1,10,@csDefButton,DEFAULT,DEFAULT,DEFAULT`
MLButton002=`261,147,036,012,PUSHBUTTON,"PushButton_Cancel",DEFAULT,"Cancel",0,20,DEFAULT,DEFAULT,DEFAULT,DEFAULT`
ButtonPushed=Dialog("MLButton")