To resolve this issue, you need to modify from the source code for now
inside the ionic project at node_modules\ionic-angular\components\tabs\tabs.js (or tabs.ts)
In different rc build, the source code of tabs.js(or tabs.ts) might be different.
Basically, the guideline is in the select tab function
Tabs.prototype.select = function (tabOrIndex, opts)
if (selectedTab.root) //this is the active tab
you will still need to file the event and the code is
Hope it is helpful for the people who is looking for the solution.
This is very inconvenience that can’t select the active tab for some scenarios.