If a window is opened Companion doesn't show up

[Fabio-LV]

After installing QuestPDF Companion v. 2026.2.2 in Windows 11 25H2, when trying to run "QuestPDF.ExampleInvoice" Visual Studio 2022 throws the exception "Cannot connect to the QuestPDF Companion tool. Please ensure that the tool is running and the port is correct.", but when trying to execute any other application, after the command "document.ShowInCompanion()" it seems that it enters a loop and the only solution is to cancel the excecution.
Companion App says the connection port is 12500, but specifying it manually changes nothing. I've tried Companion v. 2026.2.1 and 2024.10.8 but the result is the same.

[Fabio-LV]

What I've found out is that it's necessary to build the desired report in a console application — as a workbench — and only when the work is finished the final code should be incorporated into the real application.

As I work with WPF, everything rounds about a window, at least for getting the necessary parameters. And here lies the problem: if a window (at least in WPF) is shown, Companion displays nothing even though it was started, the port is active and listening, and it is listed in the running tasks by Task Manager.

If there is a straighter way for developing reports using QuestPDF (from inside the real application), I surely would like to know.