I am traveling and I do not have access to a real pc, so I can not fix it. In the best case, I may be able to fix it in about 10 days.
Ok. It is very easy to fix...1) the different icons for the different icon types only change if you change the element types by pressing the shift key, they do not change if you select the element type from the drop down list.
Your original idea was also my original idea. The "problem" I see, is that because the number of elements change on shift press, you lose the reference of where you are. With the second idea thus does not happen and allows, for example: centering an horizontal line(H) with respect to a vertical construction line (V) (assuming we start with type line) by: hover mouse in widget until H is highlighted, press shift (startpoint), click to select, press shift (endpoint), ctrl+click to add endpoint to selection, press shift (one time with fastforward, two times without, to got to line type), hover V, ctrl+click to add to selection, shortcut for symmetry constraint or right click for context menu and select symmetry constraint. With the original idea, if element1 is a circle, H and V would be different element numbers in Line type and in point type, which might cause confusion. Certainly, it has gain a lot of usability after implementing your idea of the cross icon.What I was thinking was a bit different. I was thinking that when you select the element type from the drop down list that the taskview would only list items that contain a valid selection of that type. E.g. if you select start point then any circle element would not be shown in the list or if you selected midpoint the lines would not be listed. One of the reasons I was thinking of this was as a way to reduce the length of the elements list in the taskview, because with a complex sketch this list could get very long. But with more thinking I am now wondering if this would just get confusing for the operator? Hence for at least a simple sketch, I think my other idea of changing the icon (as you have done with the "lock' icon) to represent "no valid selection of this type available for this element" is a better idea. Other may have different opinions?
I have to see it in a real computer...2) the test for valid types seems to look at the pre-selection from the mouse hover over the elements list in the task view and will work if you then use the shift key to change element types but the pre-selection changes if you move the mouse to the drop down list, hence changes the valid types available.
About the fastforward:
It is currently deliberately only working for midpoint, so skips midpoint if the hovered element does not have it. The reason for not implementing it for all types is that with the current implementation it would be difficult for the user to navigate with shift. Imagine you have an element of type point (which only has type starting point). Pressing shift would do nothing if hovering it. Inagine you want to switch to type midpoint to select the center of a circle. Because the only feedback to the user is the preselection in the inventor view, you will need to hover an element having startpoint and midpoint so that you could change with shift (which can only be an arc and we might not even have one). This would be annoying and frustrating fir the user.
However, thinking about your idea with cross icons, I am considering another usability improvement. Stop with the generic name "element" and give each element the name of the geometry (Line, Arc, Point,...), possibly with more icons, one for each geometry and type. This way, the feedback to the user is not only the inventor view, but the names and icons, so in the previous example with fastforwarding for all types, the user will hover a circle (identifiable by name and/or icon) and press shift, thereby switching to the next allowable type, which is midpoint... that on paper seems nice...
Your ideas and reports are really helping improving this tool! Thanks!
) I am using is done, unless I really want/need to see it. Elements and Constraints are the blocks and glue that are hidden, and somehow I enjoy it is that way. I fear the Tree may become too exhaustive/large. What I would certainly enjoy, is having the named datum constraints listed under the properties of an sketch, without the need of editing the sketch. So I can make copies of an sketch and rapidly change sizes, for example to loft along (across?) different sections. That I am thinking of doing in the future (though I have no problem if someone else likes the idea and wants to code it himself/herself).