This is not a bug. There are some changes in the actions functionality in the 6.0 release. They are mostly about performance improvements.
UI shows "All <plugin name> Actions" and in the sub menu "No options available"
Due to the performance optimizations the evaluation of the sub-menus is not done until the user actually opens the sub-menu.
Thanks for the reply but I don't think this issue is about the performance optimizations in 6.0.
The documentation states: "If you omit to define a solutionMenus extension containing those actions the framework generates a default "flat" menu with all the actions and the title All package-name Actions" (where package-name is the name defined in plugin-package.xml) or All bundle-name Actions when running in dev mode, because no package name is available yet."
I am defining a solutionMenu but since the metadata prevents it from being included the default "All package-name Actions" menu is displayed in 6.0. This is not what I was expecting (the solutionMenu is hidden in 5.5). If I did not define a solutionMenu then I could understand seeing the default menu.
-Darrell
You are right, this looks like a bug that we need to address in the next update release. Unfortunately there is no work-around.