This appears to be a Kentico CMS configuration issue. For info:-
The Kentico content page is made up of Zones which hold webparts. We were using a builtin webpart called "Editable Text" which defines a region on the page occupied by the WYSIWYG editor. This has a property 'HTML editor toolbar location' set to a value: "shared toolbar" - this resulted in the FitWindow button greyed out. On advice from Kentico, this property was changed to value: 'In-line toolbar' - this ungreyed the FitWindow button and gives us MaxScreen facility.
The Kentico setting must interact with the configuration in FCKEditor. This bit is obscure to us.
Re: FitWindow button greyed out [Kentico/FCKEditor]
The Kentico content page is made up of Zones which hold webparts.
We were using a builtin webpart called "Editable Text" which defines a region on the page occupied by the WYSIWYG editor.
This has a property 'HTML editor toolbar location' set to a value: "shared toolbar" - this resulted in the FitWindow button greyed out.
On advice from Kentico, this property was changed to value: 'In-line toolbar' - this ungreyed the FitWindow button and gives us MaxScreen facility.
The Kentico setting must interact with the configuration in FCKEditor. This bit is obscure to us.