Must a plaintiff seek a stay to avoid preclusion of later claims?

QUESTIONS PRESENTED FOR REVIEW 1. Must a plaintiff who has filed a civil action which asserts various claims (but whose claims do not include claims for later acts of employment discrimination or retaliation because the plaintiff has not yet exhausted his administrative remedies as to such claims and has not yet received a right to sue letter as to such claims) seek a stay in the district court to stay the proceedings in the district court until he receives the right to sue letter, because otherwise, if he does not, and the first case proceeds to judgment and he then receives his right to sue letter and he then seeks to file a second civil action asserting later acts of retaliation, he will be precluded from asserting such claims? 2. Ifa plaintiff faced with the above-mentioned situation files a civil action and files a motion for a stay so as to avoid being precluded from being able to assert claims for later occurring retaliatory actions when and if he later receives a right to sue letter regarding such later occurring claims, must the district court grant such a stay? 3. Did the Tenth Circuit err in deciding that Mr. Lu’s claim of retaliation which he asserted in his second case was precluded by the district court judgment in his first case, even though he had not received a right to sue letter allowing him to assert such claim of later occurring retaliatory actions until after the district court entered judgment against him in his first case?