Modifier List in Outliner

People are often requesting a modifier list in Properties Editor like what Modifier List addon is proposing. github.com/Symstract/modifier_list

Some people would rather keep Properties Editor without a list.

This proposal tries to reconcile both expectations by introducing a Modifiers Display Mode for Outliner. This Display Mode would be automatically activated in Outliner by a ctrl click on Modifiers Tab of Properties Editor.

It would only display modifiers of active object.

• Left activation column would be used to close/open modifiers in Properties Editor.
• Modifiers could be quickly reordered by drag & drop of their icon.
• Modifiers State could be managed through Right Click menu .
• Modifiers could be deleted, duplicated or applied through Right Click menu .
• Several items are selectable in Outliner. Right Click menu operation would be done on entire selection .

Advantages

1. No vertical space is lost by addition of a list in Properties Editor.
2. Name of modifier is always readable in Outliner if column (outliner/properties editor) is narrow.
3. Distance to travel to reorder modifiers is shorter because each modifier is represented as one line.
4. There is no obligation to use the Modifiers Display Mode. People who don't want such list can ignore it.

detail

I am reusing a mock-up made for discussion about new modifier's UI for 2.90 and was a little bit lazy. I did not want to give too much work to developers because there is already a right click menu for modifiers. We could imagine to move icons of header of modifier panel from Properties Editor as right columns into Outliner instead of using right click menu.