add note about undo/redo

issues.md

@@ -118,6 +118,8 @@ If the output file name has special characters that get replaced by underscore (
 
 # Known limitations
 
+- Undo/redo segments doesn't work through the top menu. This is a [known issue](https://github.com/mifi/lossless-cut/issues/610) that I don't know how to fix. Please use the keyboard shortcuts instead (<kbd>CTRL</kbd>/<kbd>CMD</kbd>+<kbd>Z</kbd> and <kbd>CTRL</kbd>+<kbd>Y</kbd> / <kbd>CMD</kbd>+<kbd>SHIFT</kbd>+<kbd>Z</kbd>).
+
 ## Low quality / blurry playback
 
 Some formats or codecs are not natively supported, so they will play back with a lower quality. You may convert these files to a supported codec from the File menu, see [#88](https://github.com/mifi/lossless-cut/issues/88).