Some default keymaps are not much vim compliant

[madjxatw]

For tab navigation, gt and gT are more intuitive than R and E to be used for switching tabs. "Go the first activated tab" and "Go to last activated tab" should use something else to make more sense. For page scrolling, Ctrl combination keys, e.g. Ctrl+u, should be used to scroll half page up but not a bare u as it has you confused with "undo".