Configure the option "Left arrow key never exits cell editing" (File | Options)

Here you can configure if PlanMaker allows the user to exit from cells using the Cursor Left key.

CaretLeftBehaviour

0. Off
   

   Registry Hive	HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
   Registry Path	SOFTWARE\Policies\SoftMaker\PlanMaker 2018
   Value Name	CaretLeftBehaviour
   Value Type	REG_DWORD
   Value	1

1. On
   

   Registry Hive	HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
   Registry Path	SOFTWARE\Policies\SoftMaker\PlanMaker 2018
   Value Name	CaretLeftBehaviour
   Value Type	REG_DWORD
   Value	0