Before After

As you can see in above image that sidebar only show limited post and after making changes in template your sidebar start working and viewers can view all of the post by scrolling.
How to add scroll bar for sidebar post
1 First login to your blogger account.
2 Go to template and click customize.
3 Now go to advance and click add css.
4 paste the below code there.
.sidebar #sidebar, .ss{margin-top: 12px !important;overflow-y: scroll !important;}
Now click apply to blog now visit your blog to make sure that scroll bar is working properly.
Now you can look at all post.If you face any problem in fixing feel free to ask me.