When we click into a text entry box or a scroller, such as in Text Properties boxes, it sets an insertion point. 99% of the time I find myself just selecting everything so I can change it (e.g. the pt weight of a font). It looks pretty simple to enable this in Qt, would be great if that could be added to smooth the workflow. In the livestreams I notice the Dorico team continually doing the same thing! 
Thanks for the suggestion. I’m not sure whether I agree it would always be an improvement to select all the text in a line edit or spin box that is already enabled when you click into it (since as often as not you won’t want to remove or overtype the whole value, but rather to edit what is already there in a small way), but I do agree that it would be helpful if it would be selected when you enable the control by clicking its accompanying slide switch, and we’ll look into doing that.
It’s been done before in other apps. In the case when you want to, say just edit part of it then navigating by arrow keys deselects and works as usual. But any way you folks choose.