Are new of the forum, and of GD. I have a question maybe too simple. How do I handle linked a mouse click on a object? I found only rollover. Thanks in advance to anyone who wants to help me.
Use the roll over action and the left click action. So if your mouse is over it, and the button is down something will happen. 
I just deleted mine. I used left release by mistake, but same result.
Is this a behavior or an event?
Hello! Please do not bump threads that are multiple years old, especially not near-decade old threads.
Mouse conditions and actions are used throughout the examples included in the engine, and can be read more about on the wiki. I’d recommend reading the wiki by starting in the Getting Started section on the left, reading all of the following sections, then doing at least the first 4 tutorials in the Tutorials page. GDevelop 5 [GDevelop wiki]
Thanks!