Hi Quang Vo ,
I never tried it, but can you construct an XPath expression that will identify both Plot-charts and wait for it, register the time and then wait for the first and then for the second one. Based on the timings you might sort things out. It is not optimal and timing is not down to 100 ms accuracy.

This kind of timing is also not possible with Web HTML/HTTP (C-code), you might be able to accomplish this with DevWeb protocol and JS, but that might be more difficult due to a more low-level protocol.

Thank alot JHF Remmelzwaal for your quick response.

I has aready tried to write asynchronous JavaScript function to parallel wait for element (using document.queryselector() api). Then I call this function, the script can run and return the transaction of 2 Plot chart. However if the chart loading time more than 20s, the error occurs and then the javascript has been killed (The document mentions default timeout for javascript is 20s). I tried increase the EvaluateJavaSriptTimeout on default.cfg file to 200s but it seem not applicable.

Quang Vo , TC plays some tricks to keep control over DOM etc. Not sure if you can use directly window or document object.

Maybe you have to wait for response of TC export of OT. You might go over the Blogs and see what is explained about TC.

Thanks you so much. Let me do some research for this