On smaller screens, the Insert Sitecore Media and Insert Sitecore Link dialogs in the Rich Text Editor extend beyond the viewport, hiding the Insert and Cancel buttons and preventing users from confirming their selections.
To change dialog dimensions, edit sitecore/shell/Controls/Rich Text Editor/RichText Commands.js file. Locate the InsertSitecoreLink and InsertSitecoreMedia commands and change height and/or width parameter to a value that fits the viewport of the affected device.
For example:
Telerik.Web.UI.Editor.CommandList["InsertSitecoreLink"] = function (commandName, editor, args) { ... editor.showExternalDialog( "/sitecore/shell/default.aspx?xmlcontrol=RichText.InsertLink&la=" + scLanguage + "&fo=" + id + (scDatabase ? "&databasename=" + scDatabase : ""), null, //argument 1000, 500, scInsertSitecoreLink, //callback null, // callback args "Insert Link", true, //modal Telerik.Web.UI.WindowBehaviors.Close, // behaviors false, //showStatusBar false //showTitleBar ); };