Your approach (Timer + Boolean) sounds perfect,.. Without a .capx it's hard to say what's wrong!

Here it is. Check if all functionality is there. Note that I deleted things that became unused and renamed other stuff. The code is far simpler now and I believe everything is working fine. Read the comments in the code, I put then there to guide you.

Here's the .capx:

http://examples.gamesintheattic.com/lockingOnMap.capx

Some tips

Avoid having several text objects with the same content and functionality. If you need a text to change upon selection, just change it by code, instead of piling fixed text objects and controlling their visibility.

Avoid having several identical sprites. For instance, you don't need a different lock sprite for each level if they'll look the same. Just copy and paste the same sprite on your game, since each instance is independent.

I'm sure there's a lot of optimization to do on other event sheets, but, unfortunately I couldn't take a look at them, due to lack of time.

neutrinox I don't understand why creating several text objects and pinning them to a huge invisible sprite is more effective than having one single text object with some code. By the way, you can just set text to "" when you don't need "a huge amount of text sitting around doing nothing".

And I might be wrong, but I think the number of text objects has a lot more impact on performance, memory, etc, than the ammount of thext on them.

Seriously, man... This approach of yours is definitely not effective. You are already spending time, that you could use to develop your game, to try and correct it. And the worst thing is, it's not even broken. It's just not supposed to be done this way.

Why using this approach, instead of a single Text object?

See the example below:

[attachment=0:2m8e1tre][/attachment:2m8e1tre]

Your event sheet is a huge mess. I'm optimizing it right now... Posting soon.

[EDIT] Man... It took a lot more time than I thought. You have tons of redundant events and they are certainly affecting this visibility setting.

Maybe in your solar system example you don't need the planet to rotate itself, in that case just exclude the rotate clockwise or counter-clockwise actions...

Use polar coordinates instead of just rotate and move. When you rotate and move those steps don't happen simultaneously, so the position will be incorrectly set sometimes.

This example uses polar coordinates for both automated and control dependent motion:

[attachment=0:3iy04k1g][/attachment:3iy04k1g]

Use LEFT and RIGHT to rotate moons

Another work around people sometimes use is making each sprite as an animation frame for the same sprite instead. And setting the frame according to the id.

For instance. A sprite that has 150 animation frames, each with a different sprite. Or in your example, a sprite called square that has frame 0 as a blue square and frame 1 as a yellow one.

Same here... I don't know why you cant create "Sprite"+id. But, unfortunately, you can't.

As I mentioned earlier, you must use one Webstorage variable for each level highscore. Right now you're only using storedScore.

Sadly, Construct 2 doesn't allow you to dynamically name the sprite you want to create. I have implemented a work around using a Function. You can check it on the following .capx:

[attachment=0:3imdf5du][/attachment:3imdf5du]

Left-click adds blue squares

Right-click adds yellow squares

Middle-click adds random item from family

As far as I know, you can't. If it's shown on top even when it's on a lower layer, I don't believe you can achieve this...