Question: I am trying to remove the little color marks in my Visual Studio code window by applying the VS hints, but these are apparentely impossible because these cause build errors. Here is my simplified code:

```
using System.Xml.Linq;

XDocument XReport = new XDocument(new XDeclaration("1.0", "utf-8", "yes"));
XProcessingInstruction XI = ... ;//ref to xsl stylesheet
XReport.Add(XI);
XReport.Add(...more xml content...);
string NewPageContent = XReport.Declaration.ToString() + XReport.ToString();

```

Here is a screenshot when my mouse hovers over the wavy line under ToString:

![screenshot of the VS hints](https://i.stack.imgur.com/KHAh1.jpg)

This code runs just fine, but VS hints that I should remove the `.ToString()` twice, then the code builds with an error that you cannot add an `XReport.Declaration` and an `XReport`, which makes sense.

Is this a known VS bug?

Any comments on making my code better is also appreciated.

Answer: 
This is not a Visual Studio thing, it is a [DevExpress](https://www.devexpress.com/Products/CodeRush/refactor_pro.xml) add-in showing you this message.

The message is wrong, period. The `+` operator is invalid on those objects, and if they did implement the `+` operator, it would be unlikely to result in a `string`.

Report the bug at DevExpress.
This is most probably a bug in an older version of DevExpress CodeRush. The current version might have fixed this. The DevExpress support team could not reproduce this error with the current version.