I'm a first-time user of labview, but a very experienced programmer in other languages.
It was impossible for me to find a complete, modifiable list of the changeable properties associated
with an icon on the block diagram.
I kept expecting this to be available when I right-clicked the middle of an icon in the block diagram, or a control on the control panel. At first I expected to be able to right click connection nodes and get connection properties, as well.
The expectation was initially almost unconscious, so I believe it is deeply ingrained, and might be common in other users.
This is the predominant mode of interaction in MS Windows applications, and I think it can be convenient in other UIs.
If so, Labview would be more intuitive if it leveraged this preexisting user training.