To print why a view is being rebuilt, use Self._printChanges(). You can add it as a line of code in the body property like this:
let _ = Self._printChanges()
(Remember you now need to explicitly return the computed view.)
You can also add it as a debugger breakpoint withoit modifying code:
The output is something like:
DanceStack: @self, @identity, _vm, _compact changed.
() $R6 = {}
(The register dump can be ignored.)