If you are examining a view, troubleshooting for example, we can take advantage of a recent addition (in Revit 2015 R2) called Reveal Constraints. It's a small button at or near the end of the View Control Shortcut Bar.
If any constraints have been applied, such as a locked padlock for a dimension, a locked alignment (also a padlock) or an equality constraint that's been imposed you'll see something like this; locked dimension on the left and EQ constraint on the right.
This mode isolates these constraints, making it easier to spot them. If you select the highlighted constraint you can delete it. Constraint be gone! Just add this to the list of things to remember you can do.