gurayg -I see in Hierarchy that tab screens are not generated all together when game starts. It is like ORK is being smart about it and pooling those screen GOs. It only shows one tab screen, keeps another one disabled ( I have more than 2 tab screens). I think this is normal with ORK but wanted to ask to make sure.
Yeah, this is normal.
Generally, ORK creates the UI game objects as needed and pools closed UI for later use. Due to timing it can often happen that the same UI box prefab is created twice, e.g. one menu closing and same frame opening the next menu with the same UI box.
gurayg -My tabbed UI buttons are not the default "tab button prefab" I referenced but "Button prefab" I referenced.
Everything is working but will this bite me later?
No, all good here :)
gurayg -While switching from tab to tab, I see none of the tab screens for 1-2 frames. It is like a transition but I didn't set any.
I think I can get away by introducing a background for all tab screens which would hide the transition but I want to know if this is normal.
Shouldn't be that way, unless you have a lot of buttons in those tabs that just take Unity a whole to spawn or enable.
gurayg -All my tab screens and tab button parent GO are parented to "Layer 1" GO. Is there a way to control that?
UI boxes are put on the game object of the UI Layer they're set up to use. Naturally, anything in that UI box is also on that layer. Different UI boxes can go on different layers.
You can use pre-placed inputs and tab buttons in your UI box prefab's setup - i.e. you can have full control over where stuff is placed if you don't want to rely on layout components.