Mouse focus is trapped in GtkComboBox on tool controls bar for <Space> (switch tool)

Not reproduced with Inkscape 0.48 and 0.48+devel r9942 on OS X 10.5.8

After changings the unit used for the rectangle tool parameters, <esc> deselects the current rectangle and focus is returned to the canvas (i.e. all keyboard shortcuts work as expected, unlike in related bug #687517).

In my case pressing <Esc> deselects rectangle, but focus is still in dropdown list. It become evident when pressing <Space> to change instrument. But changing instrument by pressing direct shortcut (i.e. <N> for "Node tool") works well.

> evident when pressing <Space> to change instrument

Reproduced with Inkscape 0.46, 0.47, 0.48 and current r9944 on OS X 10.5.8
Affects every popup selector (GtkComboBox) used on a tool controls bar, but only for the <space> keyboard shortcut to switch tools:

-- units selector:
- Select tool
- Node tool
- Rectangle tool

-- shape selector
- pencil tool
- pen tool

-- preset selector
- calligraphy tool

-- fill mode
- bucket fill tool

Only exception found so far:
-- gradient selector
- gradient tool

Clarification:
The code for the ComboBox used on the gradient tool controls bar seems to be the only one that does not trap the focus for <space>.

Keeping status at 'Low' for the moment because it only affects one keyboard shortcut, but e.g. allows zooming and other commands.

Please comment if you disagree.

Still repro.

Arch Linux 64-bit, KDE Plasma 5
Inkscape 0.92pre1 15054 (GTK3)