Room Editor: Selecting smaller instances on top of larger instances has odd results

[iampremo]

GM-611

Selecting a smaller instance on top of larger instances has odd results. When the larger instance is selected, it is impossible to select the smaller instance unless you first click off of the larger one.

Expected: Smaller instance is selected, selection from larger one is removed.

Note: if you double click on the smaller instance, it's properties window appears and  both instances are selected. They can then both be moved together, but in the "Instance Layer Properties" list only the larger instance is selected.

Steps:

• Start GMS2 and open the attached project Small and Large Instance Bug.yyz
• Open the Room Editor
• Click on the large instance (white)
• Click on the small instance (red) and note that you cannot unless you first deselect the large instance first
• Select the large instance again and double click the small instance
• Click and drag both instances and observe that only one is selected in the list

Example of Issue:

!Selecting smaller instances on top of larger instances has odd results.gif!

[adamrpippin]

Can confirm

[dronecloud]

agree completely.

I feel like YYG can fix this by enabling some sort of per-pixel selection on instance and asset layers. by using either a sprite's collision mask, or by using it's alpha channel. that way we could select overlapping instances/assets as long as you click precisely on the right part of them. using layers has its uses and can overcome some of this, but it isn't a solution for true freeform off-grid hand-placing when you start constructing your levels out of 2D decals.