iTorque2d - Tilemap editing eating memory up?

Ok so I think I've hit upon a bit of an annoying bug in iT2D. This project I'm playing around with is using a tilemap that's 30x20 tiles, 32pixels each. 600 tiles. I noticed as I go to edit a tilemap using this tileset, every time I click to bring up the tile sheet and select my next tile, it takes longer and longer to load. It started off at maybe a second to load, and then after only playing about 10 different tiles, I'm left waiting 15-20 seconds just for the sprite sheet to pop up.

To help remedy the issue I simply went back and cleaned up my tileset a lot (was really only prototyping with it) and cut the size down to 340 tiles. Initially it's a lot faster, but still after time it just gradually bogs down until I might as well go get a coffee between placing a single tile. I'm assuming that this is an editor issue and that iT2D is simply not letting go of the memory it uses to load the tileset, and instead just loads it into memory again and again? Memory leak?

So essentially does anyone know a work around for this? (preferably something simple) or a fix? I'm not exactly happy to run into something like this, at this early of the stage of development. It cripples my ability to use tilemaps.

Upon shutting down iT2d and reloading it I regain my speed, but it's not very user-friendly for me to have to shutdown and reload my project every couple of minutes, you know?

I am running iT2D 1.5 and developing on a Mac if that's useful information.