Het is blijkbaar een bug in IE11.
Dit zeggen ze er over bij het IE feedback programma;
Opening a new window that results in a new process being created causes the parent to lose cookies.
Opening a new window that re-uses an existing process does not have this problem.
Details:
The application makes uses of popup windows within, and the following behavior was observed in IE11 only, not IE8, IE9, IE10, or other major non-IE browsers.
Prior to opening the first popup, there are two system processes running for Internet Explorer. One is the "main" process which I presume is a thin parent process that just keeps track of everything else for the application. The other is the actual browser window you are using, for this discussion I'll call it I2.
When you open the popup another process is created, I'll call that I3, which is associated to the browser window (or tab if your settings cause popups to go into new tabs) that contains a report. When this new window is opened, the cookies are "transferred" to I3, and thus lost in I2. As a result, closing the popup and performing some other navigation in the main application window (not another popup) the request does not send the session id cookie to the server, so it treats it as a brand new visitor and does login diversion.
Also, when you close the popup window, process I3 still lingers for some time despite the window itself being closed. When you quickly log back in and open another popup, a new process is not created for the new report window/tab, but rather I3 is re-used, but what is different this time is that the cookies are "copied" from I2 to I3! As a result, closing the popup and performing another navigation in the main window does send the session id to the server, so it knows who you are and what you are logged into and works properly.
If you take a minute or two to perform that nagivation, allowing the lingering I3 to terminate, then the next popup will cause a new process (I4) to be created, cookies will be "transferred" instead of "copied" and thus the subsequent navigation will fail for the same reason as it did in the first case.
Also, this application is using PERSISTENT cookies.
De tijdelijke oplossing (die bij mij iig werkte);
To avoid this bug you can set flag in registry which turn off Loosely-Coupled IE (no more many process when you create popup window etc.):
HKEY_CURRENT_USER/Software/Microsoft/Internet Explorer/Main/TabProcGrowth and set it to 0
Groetjes hYp