refactor: add FocusListener to repaint a selected cell border
refactor: add FocusListener to repaint a selected cell border

aterai/java-swing-tips,aterai/java-swing-tips,aterai/java-swing-tips,mhcrnl/java-swing-tips,aterai/java-swing-tips,mhcrnl/java-swing-tips,aoguren/java-swing-tips,mhcrnl/java-swing-tips,aoguren/java-swing-tips,aoguren/java-swing-tips