private void richTextBox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
if (e.Clicks == 1 && e.Button == MouseButtons.Left)
{
int positionToSearch = richTextBox1.GetCharIndexFromPosition(new Point(e.X, e.Y));
but instead of MouseDown you would use the MouseOver event.
and from that point, if you have the position, you could get text from the left and right of it, and use regular expressions to find out if it is a word your mouse is at.
I have it from this example:
http://msdn.microsoft.com/en-us/library/system.windows.forms.richtextbox.getcharindexfromposition.aspx[
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I also think that someone has implemented this already using a MouseOver event:
http://forums.devx.com/showthread.php?t=143645[
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