problem creatin ExplicitFormField with RTL

I wanted to create a formField that I will use, so I started with the examples you have on the site. since I have changed the default configuration, i deleted the lines in your examples that defines family, fonts-size and line break.
what happened is that the field that was initiated with text in it worked fine, but the field that was initiated with no text at all, does not work. Meaning that when I press in the field nothing happens(no I sign appears), and when i write nothing happens. the configuration I have is :

var config:Configuration = ImportExportConfiguration.defaultConfiguration.textFlowConfiguration;
var paragraphFormat:ParagraphFormat = new ParagraphFormat()
paragraphFormat.direction = Direction.RTL;
paragraphFormat.textAlign = TextAlign.RIGHT;
paragraphFormat.marginBottom = 10;
config.textFlowInitialParagraphFormat = paragraphFormat;

I found out that the problem is cause by the Direction.RTL, and the TextAlign.RIGHT lines.

also found out that when I keep the line:
textFlow.lineBreak = "explicit";
the problem does not happen.

can you help me ? is that a bug or am i doing something wrong ?

using flash cs4.