Recently while editing entries of a directory of a commercial centre using Blogger as a sort of CMS, discovered to my dismay the sidebars have slid to the bottom of the homepage. The directory has a total of 45 posts in its homepage.
Tried to pin point the offending post by opening the posts one by one. However, found checking the post one by one to be too slow and tedious and changed strategy. By going to
Dashboard > Settings > Posts and Comments
I set the homepage to display 5 posts, then 10 posts, then 15, then 20, then 25, then 30
Found that the problem starts when there were 30 posts in the home page, so that isolated the problems to posts number 26 to 30. So can try to open posts 26 to 30 one by one and in this way isolated to a single post.
On examination, found part of HTML code for the page break was wrongly typed --> as ==> is the source of the problem. Once this was corrected to ==> to -->, the sidebars no longer slid to the bottom of the page. Problem solved.
So when troubleshooting, check a few posts in one go rather than 1 by 1.