Thank you for the additional details on the case. I am sorry to hear about the faulty behavior you have faced and will do my best to assist you on that.
The first thing I will recommend you to check is if the scaling of the monitor is set to 100%. This is what can cause the misaligned highlighting
An alternative option is to upgrade to our latest official release 2018.3.1004 which includes some fixes about the dependency between Test Studio and the applied display settings. You can use check for updates
in the product and install it, if you would like to test that as well.
I hope this will be helpful for you. Though in case you need any further assistance, please let me know.