One of the more irritating bugs I've found with Sketchup is that when I hide a layer, the program still interacts with the hidden geometry. I guess that there is supposed to be some kind of philosophy behind it, but it doesn't make much sense to me. The idea is that when I'm hiding the geometry I'm hiding it for a reason.
Let me give you an simple example...
Here a building I have created that is bisected in the middle...
Now for my next trick, I make two layers... "Floor 1" and "Floor 2" and I send the bottom geometry to "Floor 1"
I now move My top geometry to "Floor 2" and this is where it starts to get wierd. I want to to notice that there are 3 types of selectoids in the layer dialog box (Radio button, check box, and highlight) ... I will get back to that later...
Now the problem. When I try and draw geometry on the second floor, the first floor is interfering with it after I explicitly hit it.
This causes all kinds of problems such as edges migrating to hidden layers, the eraser tool "picking up" on hidden edges, and my inability to make surfaces as parts were "hidden". What irks me the most is the edge that this program is complaining about is actually on Floor 2. I can see it's right there! That's broken...
Also, why does the layer dialog have three selectors? The highlight selector serves no purpose other than not allowing me to delete layer 0 (for some odd reason). I can't tell you how many times I've done a floor, only to find that I was drawing the level in the wrong layer and now I have to move the whole thing (of course the lines that are "hidden" or "smoothed" don't go, and I have to show hidden geometry to get those too! You would think selecting something would also select the hidden geometry too on the same layer.
Here is a proper Layer dialog box
Here the highlight is what you are drawing on, eyeball is what you see. It's pretty straightforward. I can also make layers opaque, would would be awesome too.
I guess the upshot is how do you guys get around the whole layer thing. Not using the layer system is completely impracticable for me because my object I'm building is huge. I'm only on floor 3 out of 24 if I turn on more than two floors at a time, my system screeches to a halt and updates the screen about once every three seconds. (Heaven forbid I accidentally select "select all connected", which also, strangely jumps layers too
That's my rant I guess... Go head and flame away