The popup doesn't close when the viewport moves without the cursor moving

[Aster89]

Notably, this happens when pressing Ctrl-E/Ctrl-Y/zl/zh/etc. in normal mode.

The popup should close and reopen when this happens. At least for cases where the movement is vertical, like with Ctrl-E/Ctrl-Y; for horizontal movements, which happen e.g. with zl/zh, the impact is probably less important, as the popup would be drawn again on the same line(s), only displaced left-or-right. For vertical movements the pop ends covering a different line and leaving its originating line escape from under it.

[Aster89]

Well, I have to say that other plugins don't really care about this scenario. For instance, the plugin that YCM uses to show the type under the cursor, stays even if the viewport moves. Vim-matchup has a strange behavior too (andymass/vim-matchup#268).