Bueno, estuve haciendo una tienda de armas (saque la idea de un recurso y lo modifique) y tengo unos problemas con el GUI (lo hice en el GUIEditor). 
1.- Al hacer click en cualquier lado de la ventana, se compran todos los items y todas las municiones  
2.- Quise ponerle imagenes de las armas al boton. Probe con imagenes estaticas, pero el boton funciona como al 4° click; tambien probe con dxDrawImage, pero la imagen dura una milesima de segundo. 
Aqui esta el script, es del lado del cliente. 
GUIEditor_Button = {} 
  
ventana = guiCreateWindow(778,171,245,382,"Tienda de Armas Basicas",false) 
btnColt = guiCreateButton(9,30,75,75,"",false,ventana) 
btnColt50 = guiCreateButton(86,30,75,75,"",false,ventana) 
GUIEditor_Button[1] = guiCreateButton(163,30,72,75,"",false,ventana) 
btnShotg = guiCreateButton(9,112,75,75,"",false,ventana) 
btnShotg50 = guiCreateButton(86,112,75,75,"",false,ventana) 
GUIEditor_Button[2] = guiCreateButton(163,112,73,75,"",false,ventana) 
btnUzi = guiCreateButton(9,194,75,75,"",false,ventana) 
btnUzi50 = guiCreateButton(86,194,75,75,"",false,ventana) 
GUIEditor_Button[3] = guiCreateButton(163,194,72,75,"",false,ventana) 
btnSalir = guiCreateButton(139,334,97,39,"Salir",false,ventana) 
guiWindowSetMovable(ventana,false) 
guiWindowSetSizable(ventana,false) 
guiSetVisible(ventana,false) 
  
addEventHandler("abrirTienda",getRootElement(), 
    function() 
        dxDrawImage(787.0,365.0,75.0,75.0,"images/28.png",0.0,0.0,0.0,tocolor(255,255,255,255),true) 
        dxDrawImage(787.0,283.0,75.0,75.0,"images/25.png",0.0,0.0,0.0,tocolor(255,255,255,255),true) 
        dxDrawImage(787.0,201.0,75.0,75.0,"images/22.png",0.0,0.0,0.0,tocolor(255,255,255,255),true) 
    end 
) 
  
function abrirTienda() 
guiSetVisible(ventana,true) 
showCursor(true) 
dxDrawImage(787.0,365.0,75.0,75.0,"images/28.png",0.0,0.0,0.0,tocolor(255,255,255,255),true) 
dxDrawImage(787.0,283.0,75.0,75.0,"images/25.png",0.0,0.0,0.0,tocolor(255,255,255,255),true) 
dxDrawImage(787.0,201.0,75.0,75.0,"images/22.png",0.0,0.0,0.0,tocolor(255,255,255,255),true) 
end 
addEvent("abrirTienda",true) 
addEventHandler("abrirTienda",getRootElement(),abrirTienda) 
  
function cerrarTienda() 
    if guiGetVisible(ventana) then  
        guiSetVisible(ventana,false) 
        showCursor(false) 
    end 
end 
addEventHandler ("onClientGUIClick", btnSalir, cerrarTienda) 
  
function darColt() 
    local itemID = 22 
    local itemCost = 500 
    local itemMuni = 100 
    triggerServerEvent ("comprarColt", getLocalPlayer(), itemID, itemCost,itemMuni) 
end 
addEventHandler ("onClientGUIClick", btnColt, darColt) 
  
function darShotg() 
    local itemID = 25 
    local itemCost = 1000 
    local itemMuni = 50 
    triggerServerEvent ("comprarShotgun", getLocalPlayer(), itemID, itemCost,itemMuni) 
end 
addEventHandler ("onClientGUIClick", btnShotg, darShotg) 
  
function darUzi() 
    local itemID = 28 
    local itemCost = 1500 
    local itemMuni = 150 
    triggerServerEvent ("comprarUzi", getLocalPlayer(), itemID, itemCost,itemMuni) 
end 
addEventHandler ("onClientGUIClick", btnUzi, darUzi) 
  
function darMuniUzi50() 
    local armaID = 28 
    local itemCost = 150 
    local itemMuni = 50 
    triggerServerEvent ("comprarMuniUzi", getLocalPlayer(), armaID, itemCost,itemMuni) 
end 
addEventHandler ("onClientGUIClick", btnUzi50, darMuniUzi50) 
  
function darMuniShotg50() 
    local armaID = 25 
    local itemCost = 150 
    local itemMuni = 50 
    triggerServerEvent ("comprarMuniShotg", getLocalPlayer(), armaID, itemCost,itemMuni) 
end 
addEventHandler ("onClientGUIClick", btnShotg50, darMuniShotg50) 
  
function darMuniColt50() 
    local armaID = 22 
    local itemCost = 150 
    local itemMuni = 50 
    triggerServerEvent ("comprarMuniColt", getLocalPlayer(), armaID, itemCost,itemMuni) 
end 
addEventHandler ("onClientGUIClick", btnColt50, darMuniColt50) 
     
 
Ojala puedan ayudarme con esto, se los agradeceria mucho. 
Saludos.