Hi Stoyan,
From what I understood, you create a new row with a checkbox, then in the next step you want to verify the newly created checkbox. In the next step you want to verify / click the created checkbox? Now instead of clicking the new checkbox, the script keeps verifying the old one.
Firstly, have two code blocks for step 1 (writing / creating the new row / checkbox) and step 2 (verifying the new checkbox). For the second code block (step 2), you might want to parameterize the 'new' checkbox's name map to add the ObjectIdentifier / ID property of the new object. The reason it keeps opening the old checkbox one is TestComplete does not have the newly created object in its name mapping repository. You will have to add it manually. I hope that makes sense.
Cheers!
Ali