Large search&replace-all operations easily kill jEdit because of OutOfMemory errors. Give the user the option to disable the undo/redo log for search&replace all operations. A prototype implementation is attached in patch https://sourceforge.net/tracker/?func=detail&aid=3529803&group_id=588&atid=300588
A example file to test this is attached: search for ',' and replace all with ', ' (note the extra space).
The OOM error happens in the AWT thread and is not catched by the normal jEdit exception handling, so the user never get the response of the OutOfMemory error. The java process just continues to burn cpu and never finishes.