1. With a Parse Error in RULE you get an errormessage referring to a position number in the rule's string. But the editor never displayes the current position as a number, which would help locate the error.
Or highlight the error position!
E.g: unexpected element_string at position 108 of line 1.
Where is position 108 exactly? Don't want to count manually.
2. If an element is UNEXPECTED give us the EXPECTED input.
E.g. a simple mistake like not putting strings into quotation marks blocks the whole rule. The "" could be shown as expected.
