Allow modification of selected criterion text in Rule Wizard

When creating a new rule based on an existing subject, allow the prepopulated subject line ("search words") to be edited. For instance, if I invoke the rule wizard from an existing email based on it's subject line "Order ticket 20472-52937" and I want the rule to run based on only the "Order ticket" part of that subject line, there is no way to edit the existing text that has been prepopulated in the "search word"s box. . Instead, I have to completely re-type the text as a new critereon ("search words").