Temporal operator parameters lost after reopening guided rule

Description of problem:
Given EventFact1 has an EVENT role, I define following in Guided Rule Editor:

$e1 : EventFact1( this after [1m, 2m] "07-Jul-2009" ) over window:time (10d)

When I save the rule, close it and reopen the [1m, 2m] parameters are gone. Saving the rule again, possibly with some new changes, will clear the temporal parameters from .rdrl source, too.

Version-Release number of selected component (if applicable):
6.0.2.ER2

How reproducible:
-

Steps to Reproduce:
1. Use EVENT fact in Guided Rule Editor with a temporal operator (e.g. 'after').
2. Add interval parameters by clicking the clock button twice.
3. Check the rule source, save it, close, reopen.

Actual results:
Interval parameters are gone in both Editor and Source tabs.

Expected results:
The rule should be reloaded with interval parameters.

Additional info: