Selecting a block of code from bottom to top locks typing

I keep having my cursor held hostage after selecting a block of code from bottom to top and to the left margin. It locks my typing to one, overwriting character.  I have to ESC to get out of it.  I'll attach pictures, hard to explain. Really annoying! Do I have an option enabled that causes this behavior?

Selecting a block (cursor is at top far left of selection to left of "public"):

When I backspace and start typing anything is locks me to one character: