ListBox

Here's a simple version to get you going:

' Listbox help for dalaware

SuperStrict

Local MyWindow:TGadget=CreateWindow(" My Tool Box V1.0", 350,120,400,400) 'the position of the toolbox in the mainwindow
Local ListBox:TGadget=CreateListBox(50,50,290,20,MyWindow) 'the size of the listbox inside the toolbox window 
Local Label0:TGadget=CreateLabel("Working out Percentages",135,5,300,20,MyWindow) ' write text to te Main ToolBox window 
AddGadgetItem ListBox, " Formular : Value / by 100 x the percent your looking for" ' create a listbox and put text in to it 
Global Label1:TGadget=CreateLabel("Enter Value :",50,113,70,25,MyWindow) ' write text to te Main ToolBox window 
Local MyInput_1:TGadget=CreateTextField(135,110,85,20,MyWindow) ' a sort of Input
Global Label_2:TGadget=CreateLabel("Enter Percent %:",50,173,85,20,MyWindow) ' write text to te Main ToolBox window 
Local MyInput_2:TGadget=CreateTextField(135,170,85,20,MyWindow) ' a sort of Input
Global Label_3:TGadget=CreateLabel("The result is :",50,233,85,20,MyWindow) ' write text to te Main ToolBox window 
Local MyInput_3:TGadget=CreateTextField(135,230,85,20,MyWindow) ' a sort of Input

'Global Label1:TGadget=CreateLabel("Enter Value :",50,113,70,25,MyWindow) 


Repeat
	WaitEvent()
	''Print CurrentEvent.ToString()
	Select EventID()
		Case EVENT_WINDOWCLOSE
		End
		Case EVENT_GADGETACTION
		Local v:Float=Float(TextFieldText(MyInput_1))
		Local p:Int=Int(TextFieldText(MyInput_2))
		SetGadgetText MyInput_3 , v/100.0*p
	End Select
Forever

You can use SetGadgetFilter for controlling the data being entered into the textfields. I'll try and knock something up to show you how.