I'm trying with the JuceDemo project, with the latest version, download today, 03/12/2014.
When running the HTTP sample, it falls on an endless loop if I enter some URLs. If the string returned by the URL contains any special chars, like 'ñ', not encoded, replaceSection() miscalculate the position to insert the spaces (due to CharPointer_UTF8& operator++()), inserting it after the tab position, causing the the endless loop at CodeEditorComponent::CodeEditorLine::replaceTabsWithSpaces().
You can reproduce the behavior with the code below:
String text = CharPointer_UTF8("the tab is after a special char ñ\tand it will not be replaced with spaces. The space will be inserted after it");
int tabPos = text.indexOfChar('\t');
text = text.replaceSection(tabPos, 1, "XXXX");
The result text is "the tab is after a special char ñ\tanXXXX it will not be replaced with spaces. The space will be inserted after it"
I got the same result in Visual Studios 2013 as in XCode 5.1