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What's the rule for adding -er vs. -or when nouning a verb?
I would say collapser or collapsor but neither of these two words can be found on web dictionaries. Is there some other word that I'm not aware?
I'm listing all action elements of a particular web page of which some are buttons, links etc. and some provide section collapsing.
Example
Suppose you have a page with two sections: 1. a master list of elements 2. details section below/beside it
The first one is always displayed but details are initially collapsed. There is this details collapser element that when clicked expands details section and asynchronously (Ajax) loads details of the selected item in the master list.
The idea is to name the element (likely has some icon or arrow that provides visual clue related to collapsing/expansion) that performs details section collapsing/expansion. I'm currently calling it details collapser.