In the "Assign Footprints" dialog, footprints can be filtered, based on a (partial) text-filter (fourth button with the > sign). When the footprint preview dialog is open, every time the filtered footprints list on the right changes, the filter text-input field in the toolbar looses focus.
So, if you want to type several characters, every time the list changes, you have to click in the field in order to be able to continue typing.
Application: kicad
Version: (5.1.0-0), release build
Libraries:
wxWidgets 3.0.4
libcurl/7.54.0 LibreSSL/2.0.20 zlib/1.2.11 nghttp2/1.24.0
Platform: Mac OS X (Darwin 17.7.0 x86_64), 64 bit, Little endian, wxMac
Build Info:
wxWidgets: 3.0.4 (UTF-8,STL containers,compatible with 2.8)
Boost: 1.68.0
OpenCASCADE Community Edition: 6.9.1
Curl: 7.51.0
Compiler: Clang 8.0.0 with C++ ABI 1002
Build settings:
USE_WX_GRAPHICS_CONTEXT=ON
USE_WX_OVERLAY=ON
KICAD_SCRIPTING=ON
KICAD_SCRIPTING_MODULES=ON
KICAD_SCRIPTING_PYTHON3=OFF
KICAD_SCRIPTING_WXPYTHON=ON
KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
KICAD_SCRIPTING_ACTION_MENU=ON
BUILD_GITHUB_PLUGIN=ON
KICAD_USE_OCE=ON
KICAD_USE_OCC=OFF
KICAD_SPICE=ON
Related issue : loss of focus in the middle list "Symbol : Footprint Assignments"
When selecting a symbol, in the middle list, while the preview window is open, the focus goes away from the list at every click. It is as such not possible to use the up- and down-arrows to scroll through the list.