SOAP UI Assertions

I am currently working on Ready API 1.9.0 version. If a test case has a test step as "Assertion" and once i complete test case with test steps. Later when i realize i have to add another step, after successful addition of Step, all assertions written under "Assertion" step , are not visible and also Ready API gets hanged. The only way i can see my assertions back and get out of hanged situation is to exit Ready API tool by saving project. Now when i again launch Ready API tool and go to my test case, i would be able to see newly added step and also all assertions in "Assertion" step. Can any one help me out from this situation.