I have a CE 5.2 control on my page and 2 buttons, one that saves the page the other that takes them back, without saving to the listing of all items:

 

<CE:Editor id="RemarksEditor" runat="server" ShowBottomBar="false" ConfigurationPath="~/CuteSoft_Custom/Configuration/minimal.config" MaxHTMLLength="800" Width="100%" Height="150px"></CE:Editor>

 

<asp:Button ID="SaveAndContinue" Runat="server" Text="Next" />
<asp:Button ID="CancelButton" Runat="server" Text="Cancel" CausesValidation="False" />

 

If the user enters more than the 800 chars in the editor and then clicks cancel, the length validation fires and the page does not postback.  If a button is set to causesvalidation="false" the CE validation should not fire.