1. Open FlashFXP-Menu Bar-Properties-File Association
2. In the pop-up [File Association] dialog box, select "+" to add an association rule. I have linked all files of a setting
3. Select "+" in the [Create New File Association] dialog box, and fill in the file suffix you want to associate in the pop-up [Add] dialog box. Note: Be sure to add the "*" wildcard in front of the suffix . Then confirm.
4. Fill in the absolute path of your computer's local editor in the text box on the right. You can click the folder icon on the right to select the editor. And check the option as shown in the figure, and then confirm it.
After setting, you can use your local editor. Shortcut key ctrl+E