Hi,
> maybe this WaitPage method just wait for the expected URL to be available
Not exactly.
From the "WaitPage Method" help topic: "Use this method to pause the script execution until a Page object with the specified URL appears in the object hierarchy or until the specified timeout elapses."
To wait for the given object on web page you must consider the architecture of the tested web page.
Use <page>.Wait() method to wait until the page source is obtained from the server. Then, unless your page does not use scripting to get additional data and to modify page's DOM, perform explicit wait for the object that you need.
See, for example, https://community.smartbear.com/t5/TestComplete-General-Discussions/setInterval-is-not-defined-Suggestion-for-best-wait-method/m-p/206198/highlight/true#M38296 thread for more details.
