my English is not the best.
If I understood it from your first post right.
You see this Button, on click addfn() a modal is present, if you close the modal, you do not see this button, but if you click on the same place the modal opens again.
If this is right?
If yes, then it seems that this button is here but looks transparent.
round icon-start color="btnGreen" class="addBtn" and also
and anything else for example in addfn() that change the look of the button.
Is the button now visible after closing modal?
If not, can you made a format, for example background-color to a parent element?
Is there now a visual apperance of the button?
If not, is there any code that is executed regarding to modal open or modal close that have effect of button or a upper level element?
If after removing of unecessary things the button is visible, it is maybe a problem in your styling.
Best regards, anna-liebt