Returns the number of the layout (specified in the Manage Layouts dialog box) currently displayed.
Data type returned
FileMaker Pro 6.0 or earlier
If there are multiple windows open in the current file, each window can have its own layout
number value, but results are returned for only the foreground window.
You can use Get(LayoutNumber) as an alternative to the Get(LayoutName) function
if there are multiple layouts with the same name.
Returns 3 when the current layout is third in the list of layouts in Manage Layouts.