When I add a XML document into a Mantis note, e.g. an XML fragment:
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
Mantis considers the XML namespace declaration as a hyperlink and adds a "[^]" string behind:
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> [^]
If the user copy/pastes the XML from Mantis it is not valid due to these unwanted strings.
Is there any way how to switch this feature off?
You appear to be using a legacy version of Mantis; you can switch off URL processing by changing the corresponding setting in the MantisCoreFormatting plugin: go to Manage > Manage Plugins then click on MantisBT Formatting and set URL Processing to Off).
Note that recent versions of MantisBT no longer insert the [^]
.