EDIT: Woops, I missed part of your post, or you updated it and added an image.
I was about to post what is below the line. Now I have looked at the image you posted, I can clearly see that you have changed the channel name, but not the channel number. For example, the new name you use for "615 WMTVHD is "5 WMTVHD", but you have not changed the channel number. It is still 615. If you used your keyboard or remote control to enter "615", I would bet that MC changed to that channel.
Also, I don't see any channel "55", or any channel starting with 55, so naturally MC isn't going to change to channel "55 FXHD". That channel isn't listed. So, 55 isn't a valid channel number.
Note that to change the Channel Number by doing a slow double-click (about half a second between clicks) or using the Channel Number field in the top right. Also, I see that your XMLTV IDs are still set correctly, so your EPG should work fine.
Yaobing explained the sorting stuff. Once you have selected "123 ABC" or any sorting option, you can then also fine tune the display order using "Move up/down", and then save that order. Hence my custom order.
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Check the setting "Options > Theatre View > Advanced > Turn off numlock on load". If checked, uncheck.
If 55 is a valid channel number, and not just part of the channel name, then MC should jump to the channel.
Go into "Options > Television > Channels > Manage Channels", select channel 55 and look at the two fields in the top right corner of the dialogue, "Name" and "Channel Number". Channel Number should say 55.
Also, your EPG data will have to have the same channel data set to 55, because that is what the Guide display is using, I think. I haven't looked at my TV setup to confirm.
Wait. Are you doing this on a MC Client, or on a standalone PC or a MC Server?
Because I just tested the keyboard method of changing channels, once Mc was playing Live TV, and it didn't work. MC didn't display the numbers as I typed them, or change channel. I can't test on my Client using a remote control, as it doesn't have one. I think it should work here. Yaobing, has something changed here?
Channel changes using the keyboard and remote control does work on my HTPC though.