I know this thread is a bit old, but nonetheless I do believe there's some precious info to be added regarding TexStudio's vertical editing, which isn't so lackluster as one might be left to believe!
if you wish to create a cursor that spans several lines (for example, to remove some pesky spaces!), press and hold
Altand either move the arrows or press and hold the left mouse button. Of course, be prepared for a huge mess if you decided to mix spaces with tabs - but that's not the program failing you!
As @Sango specified, there is also the possibility to press and hold
Alt and use the arrows to move around. This is particularly interesting if you enjoy keyboard yoga, or you can use simply
Ctrl and, while keeping the left mouse button pressed, do the same thing!
Hope anyone finds this helpful!