Merge remote-tracking branch 'origin/HEAD' into dev/5.3

# Conflicts:
#	Source/StudyFrameworkPlugin/Private/SFGameInstance.cpp

Source/StudyFrameworkPlugin/Private/SFGameInstance.cpp

@@ -248,9 +248,16 @@ void USFGameInstance::PrepareWithStudySetup(ASFStudySetup* Setup)
 			"Restart Study"
 		};
 
+		bool bValidDecision = false;
+		while (!bValidDecision) {
 			int Answer = FSFUtils::OpenCustomDialog(MessageTitle, MessageText, Buttons);
 			const FString ModeSelection = Buttons[Answer];
 
+			if (Answer < 0) {
+				FSFLoggingUtils::Log("[USFGameInstance::PrepareWithStudySetup] The window for deciding on how to recover from an unfinished run was closed without giving an answer, repeat question!", false);
+				continue;
+			}
+
 			switch (Answer)
 			{
 			case 2:
@@ -258,19 +265,23 @@ void USFGameInstance::PrepareWithStudySetup(ASFStudySetup* Setup)
 				ParticipantSequenceNumber = 0;
 				//clear data (but only on primary to avoid data races)
 				USFParticipant::ClearLogData();
+				bValidDecision = true;
 				break;
 			case 0:
 				FSFLoggingUtils::Log("[USFGameInstance::PrepareWithStudySetup]: Continue last participant");
 				bRecoverParticipantData = true;
+				bValidDecision = true;
 				break;
 			case 1:
 				FSFLoggingUtils::Log("[USFGameInstance::PrepareWithStudySetup]: Continue with the next participant");
 				ParticipantSequenceNumber++;
+				bValidDecision = true;
 				break;
 			default:
 				FSFLoggingUtils::Log("[USFGameInstance::PrepareWithStudySetup]: Unknown UnfinishedRunDetectedDialog answer: " + FString::FromInt(Answer), true);
 				break;
 			}
+		}
 
 		// Participant
 		FString ParticipantID = "";
@@ -296,6 +307,10 @@ void USFGameInstance::PrepareWithStudySetup(ASFStudySetup* Setup)
 					{
 						FSFUtils::OpenMessageBox("Participant ID \"" + IDGiven + "\"was already used, you have to choose another one!");
 					}
+					else if (IDGiven.IsEmpty())
+					{
+						FSFUtils::OpenMessageBox("Participant ID given is empty, you have to choose one!");
+					}
 					else
 					{
 						ParticipantID = IDGiven;