I have this problem too. Just work around it.
One: when you're done writing your code in the editor, go to the "content" table in your database. Find the row that belongs to the page you're editing. Then, paste the code into the "content"(something like that) cell. When you just want to edit the content, just copy the code in the cell, copy it to the editor, edit it, and then put it back in the cell.
Two: You can edit the structure of the table. change the length the column can hold.
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