This may be an odd wish but can you tell in the changelog when you update the Allegro libraries? I only took notice of it indirectly through the fullscreen-issue. You even seem to have updated the zipfile from the build instructions, which is nice. But I can't know that I should download it again if it is not documented.

Attached an executable that prints mouse-on-land coordinates when no tile hovered.

This is useful and will go in the next release.

Maybe I'm now just being stupid but what happened to the commit for that? I know I've seen it, I even have the changed file but it doesn't seem to be there anymore.

I think Lix also does mouse capturing which may have some role to play in causing some of the symptoms (eg. maybe that's why clicking on the application icons on the taskbar didn't seem to work, if the input is still being captured and directed to the Lix window), though I thought in Windows it's supposed to release the capture once you switch away to another application.  Unless it doesn't count yet when you bring up the Taskbar via the WIN key?

The capture only seems partly removed when pressing the Win key:
a) You get a duplication of cursor: the Lix crosshair and the normal Win cursor,
but if you move the (Win) cursor, both move simultaneously (at least when on the Lix "plane").
b) It is actually quite hard to click on the Taskbar without refocussing Lix.
c) Clicking on the Taskbar seems to reunite the cursors for (at least) when not over the Taskbar but over the Lix "plane".

(That's actually quite similiar in windowed mode (apart from b) generally) though there it is nevertheless a way to effectively free the mouse.)

Edit:
- The shortcut Win+m ("Minimize all windows") brings the Taskbar and lets you produce overlapping windows by clicking on the tabs (but Lix remains on background/doesn't minimize).
- The shortcut Win+d ("Show desktop") gets you to the Desktop but if you open another window Lix gets on the background again. (Basically the same as with Alt+Tab and choosing Desktop.)

Thanks, ccexplore, for explaining.
Yeah, using the Win key to minimize always felt irregular and seems more like an escape method to get out of the program. (That's why I almost never use fullscreen when I have a choice since I want to be able to change windows easily.)

Reading Simon's question and my answering post again, I think I actually haven't answered the questions. (But they were hard to understand for me since from my viewpoint window (merely) overlapping fullscreen doesn't seem desirable in the first place.)

Alt-Tabbing to another window generally leads to an overlapping of that other window with Lix, i.e. you can use that other window and it gets visible as you can see in lixfull2.png. So insofar you get the desired results with this method.

Using the Win key: Clicking on other tabs on the Taskbar doesn't seem to produce visible/overlapping windows (at least for me). But if you use the Start menu as is activated by the Win key (without clicking on the Taskbar beforehand) then it can be possible to produce visible/overlapping windows. If you have produced such a window, even clicking on the Taskbar seems to work in this respect again.

(You can always start other programs (and see them pop up in the Taskbar as tabs), but their windows are not always visible/are sometimes in the background as explained above.)

I actually don't know how to explain that better. I actually haven't fully understood myself under what conditions exactly you can produce overlapping/visible windows. The general rule seems to be: Using keys in the first place to get to other windows brings you in a state where you can produce overlapping windows generally (even by clicking on the Taskbar) but using in first place the mouse to click on the Taskbar generally denies you such a state.

(But as explained above in almost all cases Lix remains a background image.)

Issue #262 on github

mobius discovered that (for an older Lix version) on Win when in fullscreen Lix remains on the screen (like a background screen image) when tabbing out and you cannot get to other windows.

My observations concerning v. 0.9.7 (I really hope they are accurate since it really behaves odd and particular):
- Hardware fullscreen seems to behave as expected, i.e. doesn't have this issue, i.e. lets you switch to other windows and minimizes.
- Software fullscreen:
a) If you press Win key you get the task bar but cannot switch to other tabs by clicking on them and Lix remains on the screen in the background. You can though open program windows with the popping up Start menu but only in its activation via Win key but not if you click on the Start menu button (Win 7). If you opened such another window you can actually switch by clicking on tabs until you focus Lix again.
b) If you press Alt+Tab you can get to other open windows and can change to other windows but Lix remains on the screen in the background unless you explicitly choose desktop and clicking on any other window then seems to bring Lix in the background again.

Is there a possibility to see the coordinates of the cursor position? It seems really nasty to find single tiles from their coordinates. (A workaround though would be to drag a tile around.)

Just for documentation:

I glanced through the level files and following of them contained an n as marker for no-overwrite (It is very well possible that I've overlooked levels):

Arcane:
21 - Box of Tricks
08 - CubeOut
14 - LixBot Lab
09 - Runner Stunner
11 - Sand me down

Flingsane:
05 - Falling Forever
12 - Polar Pop

Humane:
21 - Catch your Death
14 - MORE WEE CREATURES!
01 - No Killer, All Filler
24 - Pachinkube
06 - Pillarity Ensues

Insane:
23 - FALL AND DIE
25 - Hang in there!
14 - Leaky Building Syndrome
24 - Lix Recycling Plant
01 - Made to (mis)measure

Outtakes:
09 - Climb Ev'ry Mountain
21 - Times Four

This may not be helpful, but a more mild way seems to be to add something like "custom" folders, which point the users to put external stuff there, which can then be copied for a new instance. But since there seem to be three different places where custom things can go there would be much to be copied nevertheless.

Re power users:
Well you could include an example custom level, tileset etc. to allow users to reverse engineer the path.