Stylish v2.0.7 and up, or Stylem v2.2.1 and up (not tested nor supported on older versions).
Customizable edit dialog (drag n drop)
Import/export styles and stylish-custom settings
Style info listing with quick enable toggle (dbl-click to edit style, can also search within Styles, delete multiple styles)
Restores the !important button, Color/Site Rules menuitems, enable/update checks
Page button (left click for style page, right for edit page, it also posts the code. middle if you don't want to post code)
Adds search/replace to edit dialog (ctrl+F, ctrl+R, and F3)
Press ! to type !important (can be changed in edit dialog)
Select and un/comment/merge lines of text
Preview/unpreview style changes without closing dialog
Toggle styles based on which page you're on
Lots more...Stylish-Custom for Stylish v1.4.3:
https://choggi.org/misc/Stylish-Custom/Stylish_v1.4.3
There is also Stylish Editor Modified:
https://addons.palemoon.org/extensions/appearance/stylish-editor-modified/
You could try having them both installed, but you are on your own for any issues/bugs.The Style Info window can only be manually updated.
If you use new search and you hide the search bar in the customize window,
then close the edit window, open it, and then re-add the search bar:
it'll be hidden till you reopen the edit window.
If you use replace once with the caret after the search text it just skips forward instead of wrapping.