HydroModeler: Property edit doesn't disappear when it loses focus

Castronova[CodePlex]
If editing model properties and the user clicks elsewhere, the edit textbox should disappear. This is true except when the modeling canvas (composition window) is selected (i.e. the edit textbox doesn't disappear)

Start by locating the HydroModeler property-editing entry point and the composition window or modeling canvas focus handling. Reproduce editing a model property, then selecting the canvas and another control to compare the textbox behavior. Done means the edit textbox disappears when the modeling canvas loses focus, as it does elsewhere; no file or test is named in the issue.

Written by the indexing model from the issue text.