(Multi-)select EDs can too easily lead to accidental creation of element usages - propose extra steps

[MartinFijneman]

first issue, open for discussion, but noticed this during testing session (of version 10.0.4), where multiple (> 20) element usages) where created unintendedly:

in the element definitions browser, it is possible to do a selection, or a multiselect on element definitions, and with that using drag and drop create element usages. this is in itself a nice feature

the downside is that it also easily leads to errors when this is done unintenionally, and sometimes also unnoticed, leading to incorrect models.

when this is going wrong with multiple EDs selected, the deletion of these unwanted element usages doesn't support multiselect however, so this has to be done manually one by one.

proposed or suggested:

• implementation of some kind of editing mode which can be toggled, and which is somehow clearly indicated in the element definitions browser (e.g. with changing background colour, or some extra clear icon in the header):
  ** Editing mode enabled: when setting up a model, it is of course a very useful feature to easily create element definitions at the go, so with using multiselect, and without any extra prompts/ pop-ups. when you are doing this, you are most likely closely monitoring the result (as a model administrator).
  ** Editing mode enabled: when working with the model, when creating an element usage, the user is prompted for confirmation (especially for any multiselected items, e.g. a message like "This will create 16 element usages, are you sure you want to continue?")

this will make it less easy to mess up a model unintentionally by drag and drop errors that can occur quite easily.