text message delete trash can disappears I can't delete specific text messages [on hold]

Normally,when I want to delete parts of a text messages, I press on the message and "copy/more" is displayed, I press on "more" and tick the relevant text messages to delete, the trash bin appears in bottom left corner and you can delete. However it only works the first time the phone is switched on, if you want to do this a 2nd time when you press "more" and tick the relevant text messages to delete, the trash bin in the bottom left is gone and the camera is still displayed. You can still delete the entire conversation (which I don't want to do), or to switch phone off and back on again - then it works just once and vanishes again. Anyone else encountered the same problem?

iPhone 5s, iOS 8.1.3