Qlikview containers (and other sheet objects) do not raise a mouseover event. Some QV objects (like text boxes) will show the Help Text entered in Properties | Caption dialog in a popup. Others add a ? icon to the caption line to display this text.
Logic will get you from a to b. Imagination will take you everywhere. - A Einstein
I agree with the issue. In that case, you can use buttons to hide and show the charts and place them like how it appears in container. Meaning, instead of tab buttons on the container, you can create three buttons and hide and show while pressing the buttons.
In this method, you can still able to show mouse over text.