The Split-Screen Editor 
This function displays in detail all the corrections to the source text that are contained in an object. If necessary, you can adjust the corrections to your modifications here.
The split-screen editor is divided into two areas:
On the left-hand side you see the state of the source code after the changes have been implemented. The changes are identified by way of symbols displayed to the left of the source text lines:
Context lines. These are unchanged lines that the system uses to find a position where changes are to be performed.
Inserted lines
Deleted lines
Unchanged lines
Comments describing the interface of a function module.
You can edit the source code that you see on the left-hand side.
On the right-hand side you see deleted program parts and corrections that the Note Assistant is unable to implement automatically. These are displayed as context, delete, and insert blocks using symbols. (See also: Technical Details on Correction Instructions)
On the left-hand side you can do the following:
Edit manually
Select and cut, or copy and paste blocks
Note
To select a block marked with a corresponding symbol, position the cursor on the header and choose Select.
You can also select any lines. To do so, position the cursor on the first line of the block that you want to select and choose Select. Then position the cursor on the last line and choose Select again.
By choosing Undo changes, you can undo step-by-step all changes that you have made in the splitscreen editor.
By choosing Redo, you can restore any changes that you have previously undone.
You can use the arrow keys to go to the next/previous change by using the arrow keys
By choosing Concatenate, you can link two lines together.
The Undo/Redo button appears in the middle of the editor if you insert or delete a block. You can use this button to undo or redo changes one at a time. Individual delete and insert blocks are substituted.