[..]
21:43 <@ahuillet> oh yes, I know why
21:43 <@ahuillet> chest button requires *single* selection ;)
21:43 <@ahuillet> multiple selected items = we don't bother
21:43 <@ahuillet> but they're still selected under the hood
21:43 <@ahuillet> which probably leads to a crash later on, after two hours of
level editing
21:45 <@ahuillet> damn we have code to *add* an object to the selection but not
to remove it 
[..]
21:46 <@ahuillet> what it does is correct
21:46 <@ahuillet> it asks if there is a single item selected, and we answer yes
21:46 <@ahuillet> then it asks for its type, and we answer -1
21:46 <@ahuillet> and there, crash
21:46 <@ahuillet> (except when you're lucky with certain compilers and kernels)
21:46 <@ahuillet> and we answer -1 because the selected obstacle was deleted
21:46 <@ahuillet> so the correct thing to do is to write code to unselect a
single element
21:47 <@ahuillet> and make sure that the deletion functions always unselect an
element before removing it
[..]