there is one annyoying thing about button which are linked to bookmarks. I have two tables and two buttons which switch between these two tables. These buttons are placed on the table itself, but when I click on the table, even though I still see the "right" button for the switch, I cannot click on it, and it is as if I click on the table itself. Only after clicking outside of the table at another visualisation the button becomes first level again and then I can click on it. For the users its really a bad experience. I already placed both buttons and tables already on top of all visuals, but since they are actually not overlapping with these four elements its shouldn't be the reason.
As @Greg_Deckler mentioned, maybe place the buttons above the table or to one side.
What you are getting is the expected experience in desktop as if you are clicking on the visual you are looking to update it etc. In the PBI Service, this should not be an issue as the layer order of visuals on the canvas will be maintained.
the bahaviour is also in PowerBi Service and is not related to holding the crtl- button. Someone mentioned a workaround in case the user open another layer and clicking on it, for example when you putting many buttons and slicer on another empty big button, which serves as a better looking "on the top canvas".
But that won't solve my case. I have four visuals layer by layer. Two buttons in perfectly the same spot and also the two tables under it. I might either tell the users to click on another "empty" spot first in case they accidently pressed on the table or I might opted for the solution from @Greg_Deckler .