Add to Backdrop Problem

I seem to have stumbled across what I can only assume is some kind of bug.

I'm making a level editor, where a tile (active) is snapped to a grid. I have an event to add the tile to backdrop whilst mouse button is pressed.

The problem is, it doesn't add the tile to the backdrop. If you then move the mouse (whilst holding the button down), tiles are added as they should be - it's just the first tile is never created. If I use "paste into background" instead of "add to backdrop" everything works fine.

Anyway, since this is kind of hard to explain I made an example.

Please could someone take a look and see if they can figure out what's going on.

Thanks.

It appears cahnging to paste into background fixes that bug but whichever way you have it, it's gonna cause scrolling bugs.

why would "add to backdrop" cause scrolling bugs?

Both Paste Image into Background and Add to Backdrop will cause scrolling bugs, experiment with it and scrolling, you may get an interesting result.

Add Backdrop won't be erased when scrolling, only Paste Image into Backgorund will.

I've used "add to backdrop" in scrolling games a lot before and never had any trouble.

Still, I did an experiment to try and see what you were talking about. Again, I didn't notice any bugs as such. However - if you scroll away and then back again, the tiles which weren't being added to the backdrop before, magically appear! Very bizarre, but it doesn't really help me with my project :(


EDIT:
Problem solved. I'm not sure why this works, but it does.

* repeat while left mouse button down
-> make tile invisible
-> add tile to backdrop
-> make tile reappear


If anyone from clickteam is reading, it'd be nice if this could be addressed in the next build of MMF2...