The 'tie' property

An integer scalar

Valid for: All objects

The tie property is mainly used for compatibility with the older APL.68000 method of creating windows using the NEWWINDOW function, where windows are identified by tie numbers. However, it can also be used to hold any integer scalar value you choose, and is available in event records returned by ⎕EV. If you use the NEWWINDOW function to create a window, the tie property will be set to the tie number passed as the first element of the right argument of NEWWINDOW. Objects created with ⎕NEW or ⎕WI will be assigned a unique default tie value by the system, using the following convention:

10 - 99 Window, Form or Dialog

10000+ Control created using ⎕NEW or ⎕WI

Thus, if you wish to use the tie property to identify objects, and you are also using the NEWWINDOW function, it is a good idea to use the range 100 to 9999 for your own tie numbers to ensure uniqueness, but you are not compelled to do so.