Have you ever tried to select the edge of your part in a drawing and not be able to select it? We have had a couple of customers call in with this issue. At first I thought maybe that they had a filter turned on. To check to see if a filter is turned on just select the (F5) key. This turns on the filter toolbar to allow you to see what's on. In this case, it wasn't a filter.
Typically when you hover over an item like an edge or point, SOLIDWORKS will highlight what you are about to select. As you see in the picture below, nothing is highlighting when I hover over it.
All I want to do is put a dimension on my drawing but I can't select an edge! This is actually a pretty simple fix. If you go to Tools, Options, System Options, Display Selection you will see an option called Dynamic highlight from graphics view. You will see this option is not selected.
By turning this option on, SOLIDWORKS will now highlight the item you are hovering over making your selections much easier and more intuitive.
Here you can see the edge of the part highlighted.
So if you are trying to select an edge, point or arc and nothing is highlighted, check your filter (F5) first. If it is not a filter, then check the Dynamic Highlight option.
Field Technical Services Manager