Always open the Warning Box Dialog when the Del Key is pressed from the Layers Panel to avoid Silent erase of files

[pierzen]

Successive actions are often necessary for validation of data, swithching the Focus from the Map to the Layers Panel, hiding/showing data to see the background image, and swithching back to the Map Panel.

Doing this repeatively, it is quite easy to forget to swich back to the Map Panel. While the focus is still in the Layers Panel, Pressing the Del key can have quite a Destructive behavior, erasing the OSM file without a Warning Message. This will happen if the OSM File is selected and no data to send to the OSM API at this point of edition.

While Validating contributors on a community project, we upload regularly to avoid Edit conflicts and often there is no data in the OSM file at this point to send to the OSM API. It is also often difficult to reproduce the OSM file as it was at this point. Also quite annoying, we loose information about the progress of the Validation (List of Objects to review from the ToDo list for example) and have to restart validating previously validated stuff in the file.

How to reproduce

Open a new OSM layer. Either add data or not. Move cursor to the Layers Panel and either select the OSM file or Hide / Reshow the OSM data. At this point, while the focus is still in the Layers Panel, press the Del Key and the OSM file is silently erased.

On the contrary, if the OSM file contains data not yet uploaded, The Warning Dialog is showed. With the focus in the Layers Panel, we suggest that this should always be the case facilitate the validation process.

[GerdP]

I've also seen this problem in the past and would prefer to be asked when I delete the data layer. I'd say we should add an option to allow that.

[Don-vip]

related: #10832 #12483