Dialog shown slowing down

I have a very unusual problem. I have a webdialog (called dlgObservation, type modal) that reads some observations from Database, and shown on dialog’s text-boxes.

  Dim dlgObs as new dlgObservation 
  AddHandler dlgObs.Dismissed, AddressOf ObsDialogDismissed
  dlgObs.Show

Yet, even dynamically created on click every next dialog load is slower and slower. I am calling the same database, result is the same recordset, but dialog loading is clearly slowing. After 5-6 calls, it may take several second to load!

I have noticed - if I navigate away (same application, other page) and get back, loading time is once again good, dialog is once again fast.

Just to mention, dialog used to be on the page as control, but I removed it due this slowness and made it dynamically created. Didn’t help

Windows 10, internet explorer 11 & chrome.

Check the number of windows that exist while debugging.
If debugging is hard, add a label to the window and populate it with windowcount when it is shown.
You may not be killing off the previously used windows and their recordsets when you close them.

[quote=319641:@Jeff Tullin]Check the number of windows that exist while debugging.
If debugging is hard, add a label to the window and populate it with windowcount when it is shown.
You may not be killing off the previously used windows and their recordsets when you close them.[/quote]

Valid and nice idea, but no. Control count remained (80) .
Also, the single recordset I am using is closed, as well as dabatase connection.