* exists at [1]
*/
ITextRegion tagNameRegion = sdRegion.getRegions().get(1);
String tagName = sdRegion.getText(tagNameRegion);
RegionParser parser = fStructuredDocument.getParser();
if (parser instanceof JSPSourceParser) {
if (tagName.equals(fLastCheckedPrefix))
return true;
List fCustomActionPrefixes = ((JSPSourceParser) parser).getNestablePrefixes();
for (int i = 0; i < fCustomActionPrefixes.size(); i++)