Custom Inspector Invocation behaviour?

I create my own custom inspector, which on changes it will update static variables, then on another script which run in edit mode, read those variables, but those changes is somehow written to static variable but the other script which run in edit mode does not responding to changes in static variable.

but if i use default inspector (or call DrawDefaultInspector()), any changes to that default inspector is written to static variable and all scripts which read those variable responding to the changes.

what is wrong? it seem I need to call something to "wake" unity internal OnGUI() or Update() script functions when there is any changes from my custom inspector.