Consider the following scenario,
The system DPI is set to a custom value that is larger than 300%.
A third-party application hosts Internet Explorer 11 as part of its process.
The third-party application sets the zoom level to a value that is not aligned with the Internet Explorer internal bucketed values.
In this scenario, the third-party application indicates an incorrect zoom level. Additionally, you cannot find the Maximize button, and this means that you cannot maximize the UI to view the whole window.
To resolve this issue, install the most recent cumulative security update for Internet Explorer. To do this, go to the Microsoft Update.
For technical information about the most recent cumulative security update for Internet Explorer, go to the following Microsoft website:
Note This update was first included in security update 2969262.
For more information about security update 2969262, click the following article number to view the article in the Microsoft Knowledge Base:
2969262 MS14-035: Cumulative Security Update for Internet Explorer: June 10, 2014
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
See the terminology that Microsoft uses to describe software updates.