When dropping a snippet into a page, it is dropped in the drop-zone
which is the nearest of the user cursor. When moving a snippet, that
condition did not apply and the user was required to put the cursor at
the exact location of the drop-zone.
Also, for both drag and drop features, the drop zones which appeared
were not displayed correctly for full width columns, which made dropping
sometimes impossible when multiple col-*-12 were below each other.
task-1937758
closesodoo/odoo#30899
qsm-odoo
be689c53c1