could it be you're using different browsers? #1 is showing a modal dialog created through some javascript framework (dojo, I assume), while #2 is showing a true non-modal pop-up window.

This is just wild guessing but maybe it can help you find the cause:

at first glance it looks as if in situation #2 you where using a browser not capable of interpreting the framework code and thus falling back to an older method.

If that is not the case then it must be some server-side setting preventing the use of sad framework. Being a developerby trade I don't know if such a setting exists, though.

Good luck

Hi Lothar,

I have tested with the same browser in the same computer in IE11 and FF, so I would rule out the browser configuration. All users have the same mail policy, what different just the home server

I think it would be a configuration somewhere, anyone know which one? 

Hi, I raised a PMR, IBM pretty much told me it is a known issue, but still in draft.

Problem
 inotes: meeting reminder window does not show subject text

Symptom
Create meeting and set an alarm.
Send meeting invite.
When the alarm for the meeting pops up you will notice it does
not display any of the meeting details.

The issue occurs with IE only, it does not reproduce with Firefox.

Cause
The issue also only occurs when Sametime is being used in iNotes (logged in or logged out)

Resolving the problem
This has been identified as a product defect under APAR LO82653