I have some questions with Firefly, and a few bugs I found

Hi Nasirfox

Good questions and yes there are bugs. At least with the steam release of this product. Would be nice to be able to download the beta builds of this.

The questions can be answered by this.. Firefly is not a finished product. It has issues that should be fixed to be able to market games you want to make with it.

1. Why can't OpenGL mode scale to the entire window? It is stuck to the bottom left corner of the screen.
You have to code it (manually work out the sizing etc) from within Fusion.

2. For some reason, restarting the app (using F2) or frame increases the memory usage of the app? So this brings me to believe that Firefly is never unloaded from memory when restarting?
Yep there are memory leaks. Its not ready for production level gaming with that in mind.

3. Will the world editor ever be finished? You can save a world but that's pretty much it..
This product IMO is still in alpha and should warn you before you buy into this. You can code and are expected to code your own editors (everything).

4. Why does Firefly cause input lag with the built-in keyboard and mouse events? I have to use Control X for keyboard and Is Key Pressed Outside because of this.
I have the same question too. I ran a quick test and didn't get consistent results when tapping keys. Occasionally the key stuck even though I have released the key. This tells me the calls are not being fully interpreted. May be other factors at work.

5. I saw what looks to be a particle editor in the Steam screenshots, but where is that found?
You can code your own particle systems Get used to learning a lot of math and reading up on how to make your own 3D engines. Note you have the tools to do this.

6. I am aware that this has already been mentioned, but why does the window not scale back when going from maximized to windowed? You have to slightly resize the window to get it back to it's original size.
Firefly is not a finished product if you compare it to the likes of Unity and Ureal. More of a very low level interface to 3D engine through Fusion.
You are given the tools to build your own 3D engine and editing interfaces for your engine.
These days no one wants that because we have pretty good gaming/non gaming engines in the ones used to make AAA games and that you can use for free or licesnce the product. You have a choise of going it on your own (Firefly) or using a product dfesinged to get your game to the masses in a much shorter time span.

7. How can you load an Irrlicht scene? I tried loading one exported with CopperCube with all the Irrlicht versions I could select, but that didn't seem to work when using both OctTree and not OctTree, and the "Has loaded a mesh" event triggers when I try to load the scene, even though I don't see any differences.

You need to use the quake3 BSP mapping model to load big world maps or "scenes". Yes Irrlicht is the 3D base engine but I don't know if you can export from coppercube and then load into FIrefly just because you read Irrlicht.
If coppercube can export quake 3 arena maps then great.

To sum Firefly up. If you want to truly learn about 3D development, then this is a starting point. You need to read a lot about 3d Engines and how to develop your own.