Hi again…i’m sorry if i keep asking because i keep having issues of this:
When you press a selection at the GUI at the game, the bar should stop at some point. But it’s not used by force. Like for example, you picked ‘options’ at the main menu and then the main menu selection gets paused, while it’s behind the ‘options’ board.
I don’t understand. There is an action to pause a scene and go to another one (and there is another action to stop the current scene and unpause the previous one).
Lets say that when you open the sub menu, the previous one’s bar can’t be moved, but current one does
What bars/menus/GUI are you talking about? In the GD IDE or it’s a “in-game” GUI made by you? 
In game. If you played final fantasy around nes or SNES, there’s a GUI at the battle where you pick at the items submenu.
Do you have some events to show, or are you asking for tips to get it done?
I think this specific problem can be solved in several ways, let me know 
both actually.
This should move the yellow bar to yes when pressing left, then quitting the game, otherwise no, it closes this submenu and returns to the main menu when pressing right.
Adding to that, that long bar should not move.
Plus, both main and quit are in the external layouts.
Are you sure you want that in a trigger once condition?
Yup, that won’t work, even if you remove the Trigger Once, you’ll be able to move left and right only if you hold down the Return key, because moving left and right events are sub-events of pressing Return… Test it: hold Right key pressed and then press Return, this is the only way to get your events working 
To make this submenus style, I would use a “state machine”, it’s very simple:
Do you get it? Let me know how it goes