I have found a solid workaround: Use the Keyboard Shortcuts, identified by the underscored letter in the Tab…
Select a Window, tap on any Tab other than the one that is already open, then press the Command Key and the underscored letter of the desired tab.
Note that the shortcut is case sensitive, so to select a Tab with an underlined capital letter A, press "⌘ , ⇧, a" for example.
One Issue: Not all Window Menubar Tabs respond to a Tap, but there is a solid Workaround...
The Keyboard Shortcut will select most Tabs, but not quite all, macOS captures some of the Sacred Keybindings, such as ⌘, x.
Some strangeness remains: for example, if you open the Accounts List from Command Centre, Accounts, the keyboard short cuts get to all Tabs (but one), including All Accounts via ⌘, A, (using "⌘, ⇧, a" keys)
The keyboard short cut does not open Tab Expense with "⌘, x" but will open the Tab with the "⌘, ⇧, x” combination...
So it looks like with this very "Easy to Use” keyboard short cut approach, MYOB Accounting Plus 16 is fully functional under CrossOver.
During the testing phase, I have been exporting Transactions entered in macOS CrossOver, and importing them into my Windows XP Version on my trusty 16 year old Sony PCG-XE17 Notebook.
An example of Window Menubar Tab keyboard shortcuts...
