I have also experienced this in 4.5.1 using Chrome, IE8, Safari and Firefox. I was able to sort them, but upon Save and/or Publish my changes would revert back to what they were.

I tested again today before posting, and I am now getting an error:

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Stack Trace:
 [NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.editorControls.macrocontainer.Editor.Save() +1018
   umbraco.controls.ContentControl.saveClick(Object Sender, ImageClickEventArgs e) +184
   umbraco.controls.ContentControl.savePublish(Object Sender, ImageClickEventArgs e) +23
   System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +133
   System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +164
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3690

We do also get this exception on some nodes

Umbraco version v 4.5.2 (Assembly version: 1.0.3891.20719)

[NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.editorControls.macrocontainer.Editor.Save() +596
   umbraco.controls.ContentControl.saveClick(Object Sender, ImageClickEventArgs e) +269
   umbraco.controls.ContentControl.savePublish(Object Sender, ImageClickEventArgs e) +48
   System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +108
   System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +118
   System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

I have created a issue on codeplex

http://umbraco.codeplex.com/workitem/29799

Did you also remove a macro ? Or just a sort?

I am also getting thr problem whereby the macros revert to their original order when publishing ... but I haven't yet experienced the error. I see the codeplex issue has been closed but can't see any resolution ... does anyone know any more about this?

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