Registered listeners on a TkVarProxy are only notified if the variable value or validity has changed. Little bugfix to runshell, in the event that the user closes the window while the process is still running.

Got rid of lastValue/revert functionality. Changed the structure of validation/notification so that programmatic notification is a bit safer, and should not result in infinitely recursive callbacks. Now, whenever a property value changes, the HasProperties instance is notified; it then forces validation/notification for all other properties. This is done because the validity of one property may be dependent upon the value of another. Also, added ability in build.py for buttons to be added to interface.

Trying to clean up properties code, in particular to handle values of None. I think it still needs a bit of work. Also added cool little feature - a 'required' attribute may be set on PropertyBase objects, and may be either a boolean, or a function whihc returns a boolean.

Various structural changes, providing better support for list properties. Property types are now defined in a separate module.

The getTkVar method now returns TkVarProxy objects, rather than Tkinter control variables. This is so listeners can be attached to said TkVarProxies, rather than to the parent Property objects.

Changed property listener callback signature. Added ability to register a listener to either a property, or to an individual TkVarProxy. Comments and cosmetic changes to properties.py.

Widget background colour is changed when an invalid value is entered. Functionality is currently broken for list properties.

Invalid values are no longer reverted - rather, they are accepted, but there is an option to revert to the last good value, via the PropertyBase.revert method

Specific ValueError for properties.Int/Double casting errors; format string and increment explicitly set on Number Spinboxes, in widgets.py

Added ability to add listeners to PropertyBase objects - when the property value changes, the listener is called

Updated visible/enabledWhen callback structure. Now there is no need to specify the conditional properties - just a function which takes a reference to the HasProperties owner. Need to do some commenting and cleaning up before merging back to master.

Changed validation function signatures a bit. Now, a custom validation function may be passed in when a PropertyBase object is constructed. This custom function is passed the HasProperties instance, and the new value, so it is able to use the values of all properties to validate property in question. Other minor tweaks to the properties module.

Tweaks, fixes and updates to list implementation. Basic GUI functionality is working, although I have not tested it much. In particular, I haven't tested the ability to add/remove items from the list. Still in designing phase, really.

Working on an implementation of a List property. I think it's working, but need to do more testing, and to build a GUI widget for it.

Added default __str__ implementation to HasProperties. Added BET command line generation, and ok/quit buttons to testBuild.py

Changed the way that validation works. PropertyBase objects now have a validate() method which, when called, will raise a ValueError for invalid values.  The tkprop module now defines custom Tkinter.*Var classes which, when their set method is called, will call the validate() method  of their containing PropertyBase object. Validation is set up in the tkpropwidget module, and works nicely for all property types (so far).