Optimize palette for better usability regarding 'draw transitions'

[svenjawendler]

In many usability tests it turned out that users wanted to drag the transitions like the did it with states, regions etc. But this did not work. In the palette under "tools" there are all possible model elements the user can create. But despite transitions he can create all by select + drag and select and draw. Only the transition can only be created by select + draw.
This could be clearified by using a separator with only transition in one group. A little issue is the word 'tools'. This could be left out. I do not see the benefit ot it. The tools 'select', 'zoom in' and 'zoom out' are together with the diagram element 'note' in one group. But 'notes' and 'text' are no tools but 'diagram elements'.

I suggest the following reorganization of the palette:

1. Separator for transition
2. Leave out the word and symbol 'tools'
3. Add 'note', 'attach note' and 'text' to the model/diagram elements section in an own group (separator)
4. Order the model/diagram elements by use frequency -> most frequently used on top (but regions as containers for other elements go first)

[SimonEit]

I observed this issue many a'times during usability tests. At the moment the usage of the palette is inconsistent in that you can drag and drop every element onto the canvas expect transitions. Newbie Users do not understand that transitions cannot exist "alone". They assume they can drag an arrow onto the canvas and then connect both ends with the states.

This is how it works in simple drawing tools like Dia.

I therefore support @svenjawendler suggestion to separate transitions from the others elements in the palette to make it easier understanable, that they cannot be dragged&dropped.