checkbox: apply "time delay" only once

[Golddouble]

Is your feature request related to a problem? Please describe.
Normally I use Ksnip without delay. But sometimes I need it. So I go to the field and change the delay from 0 seconds to for example 5 seconds. But I need this setting only for that particular screenshot.
So what happens to me after I have taken this delayed screenshot?
Answer: One hour later I have again to make a screenshot, so I start the tool. – I wonder: Why don't I get the cross to frame the cutout? Is something wrong with Ksnip? Or with my system? – Oh no. I just have forgotten to set the delay back to "0" seconds. But now there is no other way, than waiting 5 seconds.

Describe the solution you'd like
Add a checkbox beside the field you see in the picture above. The text for the checkbox could be something like: "use the delay only one time."