The right-click popup menu is handled and positioned by Java.
Based on your feedback I had to check a few other tools such as the Finder (on macOS), Mail.app (macOS), Windows File Explorer, and IntelliJ IDEA (a popular IDE). All behave as you experience (in DbVisualizer) whereas the popup is positioned at the X point of the mouse. Right-click with the mouse too far to the left will completely obscure the name being under the mouse. So this is not unique for DbVisualizer.
You express it such as this is a defect only in DbVisualizer. Can you please mention what other applications handles this differently?
You're absolutely right! I had never experienced it before, but even my favorite IDE, PyCharm, which does UI really, really well, does the same exact thing.
I guess there were two things at work here: First, the right-click menu in the Database Navigator is huge. The only time I've seen comparably-sized ones are when careless users install tons of software in Windows and load up their right-click menu with contextual choices. However, right now I can't think of any other software packages that regularly have 20, 30, 40 lines in a context menu. I really love having all those choices available (having so much power is a major part of why I love DbVisualizer), but I will admit that sometimes I get lost among all those choices and find myself moving up and down and thinking "I know it's here somewhere!."
Second, in another comment you (or someone else) said that the right click needs to highlight the clicked item so the user will know which item they're working with, so in thinking about that comment I found myself looking at the clicked item, and watched it get obscured. :)
I withdraw my complaint, and instead turn it into a general comment: perhaps one day when you've nothing else to do you could re-think the right-click menu layout to reduce the size. Excel has broken it up into formatting icons along with normal textual choices; maybe something like that would work for DbVisualizer.
Normally when an object is right-clicked, a menu is displayed to the right of and just below that object.
However in DbVisualizer, when the object is physically located near the bottom of the screen, the menu's y-origin is moved up to ensure there's sufficient space to display the entire thing. This has the side-effect of at least partially covering the name of object that was right-clicked. With a short right-click menu this usually isn't an issue, but the right-click menu on the Database Navigation window can be anywhere from 10 to 40 lines, which means right-clicking something that isn't at the very top of the screen will probably cover up the name of the clicked object.
Also, in DbVisualizer the x coordinate of the point that was right-clicked is used as the x-origin of that menu, so if a user right-clicks at the front of the object, or on the "plus" sign to the left of the object, the menu completely obscures it. I usually find myself right-clicking in the middle of an object, thus usually obscuring only half of it. Often a program will use the x coordinate of the right-most point of the clicked object as the x-origin of the right-click menu, instead of the x coordinate of the point that was clicked.
I would attach a screenshot but I can't get one to include the right-click menu. To reproduce this effect simply right-click on an object in the Database Navigator that is within 40 lines of the bottom of your screen, and right-click at the front of the object, rather than at the end.