As Lining has suggested, check your rail connections.
I have shown it using a 'rail' instead of a 'top rail'.
But it is the same.
In fact using a 'top rail' is easier as the rail height is calculated from the top of the rail.
With a 'rail', the height is measured to the centre of the rail.
Barry.
One of the forum moderators.
Versions 6.5 to 27
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