This is seen with
Debian GNU/Linux 10 (buster)
IBus 1.5.19
When you select the emoji function, it comes up as expected, can select
an emoji as expected from the graphical window...but...
When I mouse over a given emoji (call it Smiley 1) Smiley 1 may have
three lines of technical or category data which appears at the top of
the window, above the graphical emoji set. Smiley 2, right next to
Smiley 1 may have four lines of technical or category data, Smiley 3 may
have three lines of technical or category data, etc.
Because these lines of technical or category data are *above* the
emojis, *and* the entire window literally shrinks or expands, that is,
resizes, to accommodate the number of lines of technical or category
data, the entire emoji window literally shifts up or down a line
depending on how many lines of technical or category data that emoji has.
So, as I navigate with a mouse from Smiley 1 to Smiley 2 to Smiley 3,
the window is literally resizing on the fly (and the entire block of
emojis shifts up or down), making it difficult if not impossible to use
the mouse to select some emojis.
In the best world either the technical and category data would be
underneath the graphical emoji block OR the number of lines of technical
or category data would be static so the graphical emoji block did not
resize and shift up or down as the user rolls from one emoji to the next.