Hide/Unhide rows Based on Value from Dropdown Lists

Hi, need help with the following

Cell A3 has drop down list "+" & "-".
If A3 = "+" unhide row A4:A10
If A3 = "-" hide row A4:A10

Attached is a Sample workbook.

Problem 1: I have to click away from cell A3 for the code to work. How can I activate the code just by selecting the item from the list?

Problem 2: I unlocked the cell A3 and Protected the sheet with (select unlocked cell) option. doing that rows can't be hidden or vice versa. I need this to work on a protected sheet otherwise i could have used the group/ungroup from data menu.

Any help will be appreciated. thanks

Stan your code works buddy on the unprotected sheet,

but how to make it work on the protected sheet.

thanks again for the quick reply.
Deep