MathML Palette

 Hello,
 
 I copy the structure for the "sum" to make the same with the "product". I enable the buttons that insert symbols of sets of number, eulergamma, emptyset etc. I have questions again :
 - A description of the type CHAR_T ?
 - How to unselect the inserted symbols ? 
 - Why some symbols aren't recognized (exponentiale, imaginaryI or overcheck ?)
 - How make functions to modify a mtable (move column, row etc) ?
 - How will I make to add an implementation of content tags ?
 
 I will send you a mail with the modified files (for EDITOR.A, I just changed the end of the file).
 
 Fred