If the window size of the browser is not fully maximized, the CKEditor will not display all the buttons as when the browser is maximized.
Resolution
This behavior is a new feature implemented in Liferay Portal EE 6.2 to support mobile display. Since there are so many mobile devices being released, Liferay Engineers have used screen width as a deciding factor for the way the editor is rendered. The determination of how the editor is displayed occurs upon loading a page as the Liferay platform does not keep checking the changes made after a page loads as that could negatively impact performance. That is why if the browser is not maximized and the screen width is at minimized at a certain size, then the CKeditor may seem to be missing some of the editor tools that normally appear with a maximized screen.
Workaround
Maximize the page and then reload/refresh the page. The full range of tools and buttons on the ckeditor will now be available for use. Then minimize the browser page to the desired size and as long as the page is not refreshed, the full range of buttons available in the editor will be available for use.
Additional Information
For more information, please refer to LPS-38359