Magical disappearing keyboard! A long-standing bug?

This is an issue I have experienced pretty much since day one, when I got my iPhone 4 in 2010, but I thought it was high time to write a post about it. Forgive me if somebody else has already done so. When I am on Safari or in an app where the on screen keyboard is presented for form field entry, If I drag my finger around on the screen, say, to get a better understanding of the form layout, I find that when I return to where the keyboard should be, it has been hidden. The field I was editing still has focus, yet the keyboard vanishes for some reason I don't understand. Is this supposed to happen or is this a bug?

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I've only just started encountering this one

I've had an iphone since 2013, but I didn't have problems with the onscreen keyboard disappearing until the past couple of months. I've found ways to bring it back that work for the most part, but yes, especially if this has been around for a while, it needs to be fixed. Unless we're just missing something that everyone else already knows about?

Hi. Are you by chance using

Hi. Are you by chance using an external keyboard with your devices? If so, any time you connect the external keyboard it will make the onscreen one go away. You can bring it back though by hitting the very top right key on the external keyboard and that will toggle the onscreen keyboard
On and off
Danny