A good idea would be to talk to the gimp developers and work together on UI usability issues in the future, the results would be included in next revisions of HiG for similar types of apps.

I agree with most of Marek's comments. In particular, the monster multisection toolbox is already removed in the latest CVS. As for working together on usability, I'm all for that! So...

Today I finally tested the latest development Gimp (1.3.23). Below are my impressions focusing on my area of interest in Inkscape, with my view on what is good and what is bad in Gimp (and what we should or should not borrow). Just a few first impressions, I did not do in-depth testing. Probably I'll have more to say after I've used it for some time.

Feel free to forward this to a Gimp list (drop me a note if you do so, so I could track responses).

Summary: Sure the new Gimp is impressive. And MUCH more usable than 1.2. But in the usability department, there are still things I strongly dislike. I do not want to say they are necessarily errors, since this is subjective, but I think there are other people out there who would agree with me on at least some of the points below.

The majority of palettes (dialogs) are sill not transient and "sink" readily when you switch to the document window that overlaps them. Working with a maximized document window is therefore next to impossible. Some of the dialogs/palettes are transient, though - I think it's those that can only apply to the current document and are more or less "modal", i.e. you cannot do anything on the canvas while such a window is active (examples are Levels, Color balance, etc.) Making such modal windows transient is indeed a step in the right direction, as in Gimp 1.2 even they could be buried easily (and confusingly for most users). However, having to dig out my primary toolbox from under a pile of windows still drives me crazy.

Dockable tabs/palettes are cool, no arguing about that. However, they only dock to each other and not to a document window. The main toolbox is also exempt from docking. This means that although you now have a way to reduce the number of windows on your desktop, you still have at least three windows (document, toolbox, a group of docked palettes) that you'll have to alt-tab your way through.

On the plus side, all floating palettes remember not only position but on/off status and all docks across sessions: when you restart Gimp, it reopens all the palettes it had opened last time. I wonder if we have to do the same in Inkscape (currently only size and position of dialogs is remembered).

Weirdly, the single-letter keys for switching tools only work in the document window. When you have focus on the toolbox, you cannot press "t" to switch to text tool, even though the tooltip at the text tool button suggests that you can! This is despite the fact that tools seem to be global, i.e. you cannot have different tools active in different document windows. Similarly, I cannot press crtl-z to undo an action that I just did in a palette (e.g. trashing a layer); I must switch to the canvas (and remember, it's my reponsibility to select the correct document window, if I have several open!) and press ctrl-z there! I think this is another example where the idea that palettes are standalone non-transient windows in their own right plays bad for usability.

The palettes are so "independent" that they don't even care to track the current document. Switch from one document to another and watch your Layers palette, for example. Does it show you the layers of the new document? Nope! You have to use another palette called Images to select what document is being displayed. Moreover, the Images palette only affects those palettes that are docked together with it - if you have e.g. a Layers palette and a Path palette in two different floating windows, you'll have to add an Images palette (or an Image menu) to _both_ these windows and switch images manually in each of them.

I think this is very inconvenient. A much better solution is what is being implemented in Inkscape: all floating windows always reflect the active document (i.e. the one whose window has focus). Also, they are re-transientized to the active document when you switch document windows - this means they always stay on top, but are minimized when the _last_ document window is minimized, are restored when _any_ document window is restored, and do not clutter the taskbar.

Another problem with Gimp's palettes being too independent is that you can't leave them using keyboard, because a palette does not know who to give focus to. That is, you can pop up a Layers palette from within a document window using keyboard (ctrl-l), but you can't go back using keyboard except with the help of your window manager (e.g. alt-tab). So if, for example, I have edited some value in a text field in a palette and press Enter, it does affect one of the documents, but the focus remains within the palette and the affected document does not pop up if it's buried. Esc also does nothing within a palette. Moreover, there's even no keyboard way to close a floating palette - Ctrl-w only works in a document window but not in a palette (why?). (By contrast, in Inkscape, Ctrl-w closes a floating dialog, Esc moves focus from it to the document that it's currently reflecting/affecting, and so does Enter in text fields.)

Misc small things:

Zoom shortcuts are inconvenient. "-" on the keyboard zooms out without shift, but to zoom in I have to press "+" with shift. Keypad - and + do not work at all.

Distance measurement tool snaps to horizontal if used with ctrl and to verticals if used with alt. More convenient would be using ctrl only to snap to closest n*step angle where step can be set in preferences (e.g. 45 degrees). (This is what we're going to do in Inkscape.)

In fullscreen mode, no floating palettes can be seen. If I switch to them by alt-tab, I don't see my document window anymore! I switch back to document and the palettes are hidden again.

P.S. Regarding our recent discussion of Gtkmm/Glade, Gimp seems to use what we use now, i.e. plain C. Does this mean that if we switch to Gtkmm we won't be able to borrow code, such as dockability, from Gimp?