It can be done easily. Define a "String" s to show the value for variable v(double) and add a String GUI element into DrawingPanel.
You can set up the x,y coordinate for the String (to where you want the string to be displayed!).
Add the following code s=(int)(v*1000.+0.5)/1000.+""; will display values as you want in the previous message.
(if v<0 then change 0.5 to -0.5)  ;D