Currently you need to try not shaking your hand when moving your cursor to a thin submenu of the context menu, such as "Create New >". Some context menus have 2 submenus.

I'm requesting an accessibility feature that would allow users to click on these submenus to "freeze" them open, like the context menu's main buttons.
Clicking on these "frozen" submenu buttons again would make them go back to normal.

This would be useful for mouse/touchpad only users with shaky hands who can't move the cursor in a precise horizontal direction.

KDE dev said that QT currently lacks support for this.
https://bugs.kde.org/show_bug.cgi?id=487022#c8