The title says it all: The property dialog of controls should allow inspecting and changing the default value.
Here's how it could look like.

Sometimes I wand to re-define a default value without actually changing the current value.
current steps
- copy the current value elsewhere
- enter the desired default value
- right-click...data operations...make current value default
- restore the original value (could lose data in case of DBL!)
After implementing the idea
- right-click...properties...enter default value...OK.