displaying issue when switching between RTL and LTR in Win Form Rich Text Box

Question

I tried the same thing in both Win form and WPF form and seems this only happens in Win Form. Basically what's happening is that I have a RTB control in Win Form, and 2 buttons: RTL and LTR to adjust the alignment.

button1 clicked:

richTextBox1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;

button2 clicked:

richTextBox1.RightToLeft = System.Windows.Forms.RightToLeft.No;

That's all I have. when I paste text into RTB and click on the RTL button, it left a big gap in RTB. I noticed this will ONLY happen if the scroll bar is presenting. if you resize the form, the gap will go away.

see link for the screenshot: screenshot of the issue

I tried everything I could but couldn't figure out why it's happening. I suspect it's a .NET bug, does anybody have any idea?

Answer 1

The only solution I could get to work is to reset the text when you change the RightToLeft property of the RTB control and adding a Application.Doevents().

Like this:

private void buttonRTL_Click(object sender, EventArgs e)
{

    string txtRTF = RichTextBox1.Rtf;
    RichTextBox1.Clear();
    RichTextBox1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;
    Application.DoEvents();
    RichTextBox1.Rtf = txtRTF;

}