We've known for years, about the mysterious dropped sidebar. Sometimes, we see similar problems, in other blog performance.
- Gadgets missing.
- Gadgets visible, but they don't work.
- Gadgets visible in the desktop view - but not the mobile view (or, vice versa).
- Posts that are unreadable - or worse, previously published posts, in that index page, that are unreadable.
When instructed to use "HTML" mode, to install a specific tweak, you may never know about one good rule to follow, when editing HTML / XML code.
If you don't know the purpose of a given HTML phrase or word, leave it alone.
HTML code, which may appear as gobbledegook to the untrained eye, contains no unnecessary characters. Even adding or removing a single space, in some places, may break a gadget, page, or post - or worse, the rest of the template, following the broken gadget, page, or post.
If you have a problem with the blog, in general, you may be advised to "Reset the post template" - or maybe "Reset the gadgets". If you have a problem with a specific gadget, page, or post, you'll use a different technique.
Sometimes, when you use "HTML" mode in gadget, page, or post editor, and you break a gadget, page, or post, you can repair the broken gadget, page, or post by toggling between modes.
- Prepare the gadget, page, or post.
- Toggle from the current mode to the other mode.
- Toggle back to the "current" mode.
- If you need to finish the problem reset, in the "other" mode, toggle to that mode.
- Complete the reset.
- If you're using the gadget editor, save the gadget.
- If you're using page or post editor, re publish the page or post.
If this procedure does not work completely, you may have to next remove all formatting, if you're editing a page or post.
And when you're done repairing your mistake, backup the template. The next time you make a mistake, you may be using the Template Editor - and a template backup could save your sanity.