Selecting and deleting everything in markdown fields doesn't work

[Yelinz]

If the whole text of a markdown field is selected and then backspace or delete is pressed, then nothing happens with the selected content.
This only occurs when the whole text in the markdown field is selected, single words or lines still work.

[Yelinz]

The problem doesnt stem from ember-caluma, plenty of other little bugs aswell which are also in the codejar repository.
Tested the following issues and they apply here aswell.
antonmedv/codejar#67
antonmedv/codejar#73
antonmedv/codejar#75