* On lines where the variable type is obvious from inspection, avoid repeating the type using auto.
* When possible use a ranged for loop instead of begin() and end() iterators
- Abort mode via ESCAPE added
BoxZoom, BoxSelection and BoxElementSelection
- Change the cursor to give the user feedback about active mode.
- Abort mode via ESCAPE
An empty block after a conditional can be a sign of an omission and can decrease maintainability of the code.
Such blocks should contain an explanatory comment to aid future maintainers.