some time ago i started a thread for the above problem
i came accross the same problem again, but this time i realised that
whenever a chart sheet appears, the Worksheet Menu Bar is replaced by the
Chart Menu Bar.
all this time i thought the Chart menu was inserted into the Worksheet menu bar, which was not the case.
So i solved my problem by inserting my menu on both the Worksheet menu bar as well as the chart menu bar.