i am using Developer Mode + bug/debug icon

when i am editing Lead's Kanban view (debug icon -> Edit View: Kanban) and added below code, it is working fine.

'style'

.o_ActivityListView_addActivityButton, button[title="Mark as done"]{display:none;}

'style'

but when adding this code in Tree/List View it is saying that style is not allowed, how i can achieve for Tree View? is there any work around or from somewhere else or something else to achieve this? please help.

i have tried this but not working:

button title="Mark as done" attrs="{'invisible': [('create_date', '=', True)]}"

the code for button through Inspect is as below:

button class="o_ActivityListViewItem_actionLink o_ActivityListViewItem_markAsDone btn btn-link shadow-none fs-4 fa fa-check-circle" title="Mark as done" aria-label="Mark as done"

also i want to hide below button +SHEDULE AN ACTIVITY 

button class="o_ActivityListView_addActivityButton btn btn-secondary p-3 text-center" i class="fa fa-plus fa-fw" Schedule an activity

regards