Well, (1) the extension rotation is totally eye candy, no game functionality is affected, it's completely irrelevant unless for scenario builders (like myself) and (2) the signal spacing is important to change only once, after you have set a default on your session you are done.
Sure, rotating those extensions is just eye candy, and while I disagree with your assessment about signals spacing (if you really care, you would change it more often when your trains get longer or shorter over time; If you don't care, you never change it at all), I understand that those functionalities are less important then one-way-roads, and definitelly not worth spending too much time on in their own right. I'm not even saying you personally should change anything about them - rather, I think WE, the community, should come to some common concensus about how Simutrans menus should work, which can then be implemented by whoever happens to have enough time. Which I realize would likely be noone, but still.
I think the way you designed your menu has implication you don't yet realize. The revolutionary thing about it is that up until now, we had buttons to call menus, we had buttons to call windows, we (rarely) had buttons to toggle something, and we had buttons that called a cursortool; you change all road icons to do both, call a menu AND call a cursortool. Once you do this, why not do it more often?
For example, p192c has a demolish-tool and a demolish-menu, currently two icons, which could very well merge into one without any loss in functionality either way. Same (perhaps to a lesser degree) for the view-tool and the view-toolbar. And perhaps it would even be rather easy to implement with a simple boolean flag in every icon that calls a menu, which would indicate that the first tool of that menu is auto-selected - quite straightforward.
If that would be done, you could eg. create sub-menus for each type of signal - since you always call the first signal, you can always build a signal with the function you wish for, or you first select one that looks different. Since you said it's persistent, that would be true for such sub-menus as well, so once you choose one, the main-icon will call that one next time. And because of that, you could even use it for stuff like tracks... so essentially, your menu would consist of "build a way", "build a tunnel", "build a bridge", "build electrification", "build a block signal" to "build an end of choose signal", "build goods station", "build pax station", "build station extension", "build depot". I don't think that would be too bad, and if it would be done, I wouldn't mind at all. It's just very different to the current behaviour.
If, instead, you would just add those five icons but NOT show them automatically whenever you call any road tool, the functionality would be largely the same; if they are in the road menu nothing would change at all. The user would perhaps need one more click over the course of the whole session, the one to call those tools to put them in some corner - if they are not part of the road tools anyway - so essentially nothing. However, since you don't mix up menu-calling with tool-calling, there is no reason to do it with anything else either, it would have no resemblance to all the control-click-options, and therefore it would fit in the canon of how Simutrans works a bit better.
Yes, I'm fully aware that you might say it's a slippery slope arguement, but the problem is that the slippery slope would be the better option over plain design inconsistency. That's why I think it's important to talk about this in general, not just in relation to this function.
