Magic Mouse: Why Does It Need to Be Clicked When Restarting or Booting from Shutdown to Get Detected All the Time?

Question

Hi. I'm using Snow Leopard via USB external drive (the hardisk is blank- testing something with Leopard). When I start the late 2009 iMac and boot with the Option Key, I need to click the Magic Mouse all the time so the mouse can be detected and move the cursor to the Snow Leopard icon ( in its boot menu ). After the Magic Mouse is detected, it's good from there.
Is this normal or there's something wrong with the Magic Mouse? The keyboard doesn't need to be pressed though to be detected, it's detected each time.
Thank you in advance.
God bless, Rev. 21:4

Answer 1

I cannot see why you should have to click the magic mouse in order for it to be detected ... unless you have changed the batteries.  See my notes which cover the points made in your other recent post.
Batteries.  Here are a few notes I've put together.
Whether you use regular or rechargeable batteries you should buy the best. Discounted or unbranded batteries are more likely to give a depleted performance and may be of irregular size, often leading to connection problems.
Apple’s own brand, Eneloop and Energiser appear to be the best. Rechargeable batteries for the standard Magic mouse are unlikely to exceed eighteen days before needing a recharge although the mouse itself can be a limiting factor.  I have seen reports that some Logitech mice vastly exceed this.    Apple may suggest more in their sales blurb but this is a realistic expectation.  The benefit (if you are organised) is that you can always have charged batteries available.  Regular batteries will give you between 25 and 35 days before they need to be replaced. Note.
Never mix old and new batteries or rechargeable and regular.
The notes above are based on my personal experience, not shutting down my machine and using it for around four hours per day.  Note.  Monitors do not always faithfully report battery strength, particularly the rechargeable ones. 
When checking your mouse or keyboard batteries ... Turn off the device. Remove the batteries, Clean the terminals both inside the battery compartment and the batteries themselves. Replace or renew both batteries. Turn on the device.  You should get a blinking green light if the device is paired. Click the mouse to activate it.  The green light becomes steady.