I have a problem. I should divide a JTextPane into two columns. And
there should be a line between them.
There are some problems.
1- The line should be moveable so the column width can increase or
decrease.
2- The ext in the text pane should not exceed rendering area. If user
editing in left column last element in the left should pass right
column. If it is right column user shouldn't edit.

I have a algorithm. I think to add two text pane and a panel between
them. With drag and drop I arrange the width of text panes. But I think
it is not an efficient algorithm.
Does anyone have a better idea?