In theory I thought I knew how to do this - in practice I can't get it to work.
When Form 2 loads I want it to merge its menus with Form 1. I have set the Automerge property on Form 2's menu to true, but set Form 1's Automerge to False. Form 1's menu contains 3 headings, which have a Group Index of 2, 3 & 4. Form 2's menu has one heading with a Group Index of 1. The form styles are fsNormal.
When Form 2 loads, the menus don't merge. Which blindingly obvious thing have I missed?