X11 blinking cursor in text window like 'gvim' - only halts if moved-over another X11-win

[L A Walsh]

I don't recall this always being this way as I keep running into
a problem with my input going into the wrong window.

I've noted I seem to be relying on which editor(i.e. gvim)
window in X11 has focus by noting that it has a
blinking square cursor in the window at the cursor's
current position in the edited text.

If I move the windows cursor to another editor window in X11,
the blinking cursor moves to the new window, but if I move
it to a native window, the blinking doesn't stop.

Has this always been this way?