The Build in your signature ?  Windows Vista?
 
X20 mouse
 
Make sure your using the best USB port on your PC designed for charging & the BIOS is set to use charging use - for quickest charging
 
Set MB BIOS to Allow or Stop USB charging when PC is "soft off" after shutting down Windows
 
If it is the MB in your signature --> EVGA 780i SLI FTW Mobo - I'm not sure you have a charging rated USB port - check your manual
 
        Charging rated USB ports allows more Amperage to charge thing faster
 
 
Use the switch on bottom to turn the mouse off to save battery while watching movies (middle position)
 
Source: https://www.techpowerup.com/review/evga-x20/6.html
(excerpt)
"EVGA states a maximum battery life of 60 hours without illumination and 24 hours with full illumination in 2.4 GHz mode; no details are given on expected battery life in Bluetooth operation"
 
To control or turn RGB off --> use the software  EVGA UNLEASH RGB v1.0.20.0 (X20/X17/X15/X12 drivers)
 
You asked "what is that little extender for and/or better said, how do I use it?" 
     Are you asking about the sleeve the adapter was near in the photo (item T in manual) ?
 
Plug dongle into extender on large side & the USB cable in other side - to route receiver to another location if you get interference issues
 
stated in manual -->under 2.4GHz Wireless Mode "Use extension adapter to connect USB receiver and USB charging/data cable"
 
 
 

Apologies for the Signature, I almost never post on this forums but I have edit my signature to reflect new rig.
 
I still find it cumbersome as opposed to the X17 which it was wired but didn't have major issues except for the middle scroll wheel of course.
 
I open the Unleash software and it takes a second or so for the X20 to appear. It hasn't gotten to 100% charge yet. Played for about 4 hours today and it used almost 50% of the battery wireless and sorry but if I have to remember to turn it off every time I am going to watch a Movie or TV show I soon toss it like a 2 dollar, well... you know.
 
If I ran the cable to charge it whether from a 2.0 or 3.0 USB port the Unleash doesn't tell me what percentage is charging only that it is. Unleash software and Windows don't see eye to eye on the percentage the mouse is charged. Not a big deal but a bit confused by it.
 
I'll check the Bios and see if there is an specific USB Charging Port that I should be using instead of the 3.0 where I now plug the cable in.
 
The EVGA Dongle where the receiver is taken out and now there is a female usb port has the other end the mini usb port, how or why do I need that dongle or is that just to carry the wireless receiver? Again, perhaps I am thinking too much but I don't how to use it.
 
Thanks
 
P.S.: Don't misconstrue, I like the Ergos of the mouse, perfect for my hand, the old G9 was good but I was never able to get along with it due to the Ergos so when I saw the X17 on Sale with the Z15 KB as a combo, I had to pull the pin but this little and quirky things are doing me in.
 

Ok, lets see if I can get some traction here because this is ridiculous to be honest
 
I have a Remote KVM but the main/default/#1 PC is my working/Gaming/Asus rig and the KVM #1 button is for my rig, the other PC hardly ever gets use right now.
 
I also have a USB extension for both the mouse and KB to my couch (I work and chill from it). Please, before you tell me that it may be the USB extension cables, let me preface this by stating that I also have a spare KB and the Logi G9 and I have no issues whatsoever with them.
 
My Antec DF700 Flux PC has 2 front 3.0 USB port and the EVGA/Dongle Wireless Receiver is connected to one of those ports. When I am using the wireless option via the Dongle/Receiver the mouse works ok but as soon as I want to insert the charging cable (normally I do this when I am not Gaming) the mouse *STOPS* dead on its tracks. The Unleash software sees it but it does not work, if I move it to Bluetooh it does not work either. I hear the sound the PC makes when it finds a device. 
 
The only way to get it back to work is if I unplug it, some other times switch the KVM works and/or unplugging it from the extension. Some other times the same thing happens with the KB but right away I just unplug it from the extension, plug it back in and on my way I go but the mouse seems to delay this more.
 
I just want to use the mouse w/o having to recur to any of this hassles. Am I destined to use it wired only? 
 
I am not even going to sweat not knowing what the dongle does or what/how one can use it that has been tabled for another time.
 
And NO, I rather NOT having to RMA it because it costs me around 15 bucks to do so I am willing to try different things.
 
P.S.: I was unable to find anything on the Bios about direct charging USB port but I do remember reading something about it I just can't remember where or if it was for this PC case.
 
P.P.S.: If I connect the cable to charge the mouse while I watch a TV show (even if it freezes) every so often, the PC makes that noise like a device is being connected but the mouse still won't move, then it does it again and I think it will work this time around but to no avail. It is very annoying because it may be an IRQ conflict but I can't put my finger on it. 
 
Also, this may not be important or pertinent but Device Manager shows 3 HID Keyboard Device and 2 HID-compliant mouse but neither the Z15 nor the X20 show up on DM. Now, still in DM but if I go to the Bluetooth section the EVGA X20 Gaming Mouse shows up there.
 
Thanks