How to make a very narrow window?

for 1) try Shift+<F11>

Thanks!
Shift+<F11> is very close to perfect. For practical purposes it also solves (2.) I am not trying to prevent myself or anyone else from deliberately modifying the stencil, but rather prevent myself from accidentally modifying it, and it's difficult to modify accidentally when there are no decorations.

The only thing missing is saving the state of "Shift+<F11>" when the file is saved. If we can do that somehow, the problem will be solved and in my opinion we will have a nearly complete solution for stencils.

I retract the third part of my problem. I found where to start in he code (inkscape.cpp and menu-skeleton.h)

Thanks ~suv, that solved my question.

Yes. This now becomes a policy question.

There are three conceptual approaches:

1) Make a tiny change to save the state of the focustoggle variable. This is a three-line change treata focustoggel the same way that is_maximized is currently treated, as part of saving the wingow geometry.
2) Generalize to save the state of all the variables related to window display, not just focustoggle
3) treat a stencil as a new type of persistent object rather than as an ordinary document.

As a systems architect, I favor the third option, because a stencil should have some "live" behavior that is not present in an ordinary document. In particular, the items inthe stencil might properly be alligned in rows and columns in an array that adapts to the size of the window. However, as a user, I prefer the first solution, because it gets essentially all of the needed functionality with a three-line code change.

Another topic to consider before about storing this setting on the document level: usability. Unlike the maximized state this could potentially cause usability issues since it modifies the GUI radically (i.e. all visible items are gone, only the shortcuts work) and can't be 'undone' without knowing this (undocumented?) keyboard shortcut. If a new user opens a document created by someone else (or downloaded from the web) that was saved with this setting he/she could well be lost and stop using Inkscape thinking 'it's broken'. The menu- and toolbar-less UI would at least need one button or context menu entry to return to the normal GUI.

I don't know the history of this command - nor do I remember how I discovered it. But it is rarely mentioned and not listed in the official shortcut reference <http://inkscape.org/doc/keys047.html> and only briefly in the Inkscape manual <http://tavmjong.free.fr/INKSCAPE/MANUAL/html/View-Misc.html#View-Misc-HideShow>.

Personally (I'm not a dev but do test many files attached to bug reports) I got so annoyed by the number of documents saved with 'inkscape:window-maximized="1"' that I changed the preferences setting to disrespect any saved window position/geometry, even for my personal files where it would be useful of course (I *don't* like maximized windows ;).

i.e. imho even from a users perspective one could question whether the 'three-line-code' is the best solution. For your current issue it certainly seems a compellingly simple solution promising a quick fix (if you know to code the three lines).

Incidentally as a general fix any windows minimum size can be forced in KDE using the windows Advanced > Special Window Settings (click the window's application icon which is usually top-left). Even with the toolbars I could set the size arbitrarily small; but Shift+F11 is neat.

Saving window settings on drawing close on a per drawing basis would be great IMO.