Version:            (using KDE Devel)
Installed from:    Compiled sources
OS:                Linux

katepartui.rc defines a reasonable amount of groups for menu actions but not for toolbar actions. 
For example, there are:
    <Action name="edit_undo" group="edit_undo_merge" />
    <Action name="edit_redo" group="edit_undo_merge" />
    <Separator group="edit_undo_merge" />
    <Action name="edit_cut" group="edit_paste_merge" />
    <Action name="edit_copy" group="edit_paste_merge" />
    <Action name="edit_paste" group="edit_paste_merge" />
but only
  <Action name="edit_undo" group="edit_operations" />
  <Action name="edit_redo" group="edit_operations" />
  <Action name="edit_cut" group="edit_operations" />
  <Action name="edit_copy" group="edit_operations" />
  <Action name="edit_paste" group="edit_operations" />
This prevents applications which embed kate part from filtering actions shown on toolbars. For example it's not possible to keep undo/redo and remove copy/paste from a toolbar.
Everything would be ok if toolbar actions had the same groups as menu actions.