Let's take a look at the Model navigation panel, which can be found on the left side of your Vertabelo workspace.
In Model structure you can navigate through elements of your model and manage them. Double-clicking on any element in the Model structure will set the focus of the diagram to that element. Right-click on any element to manage it.
Sometimes, while working with the models, icon of a given element may get a badge of an error or a warning.
In such situation open the Problems menu, and resolve the issues.
As you can see, there are two categories: Errors and Warnings. You may locate the problematic element by clicking on the error/warning text – the element will get selected.