Change order of features when browsing with popup footer arrows (or using slideshow mode)

[el-srabo]

Is your feature request related to a problem? Please describe. I have a travel map with different layers, each containing markers. All markers name begin with a date (e.g. 2023.01.01) or a date range (2023.01.01 / 2023.01.31). Let´s say I have the markers "2023.01.01" and "2023.01.03" in Layer 1, and "2023.01.02" in Layer 2. When I browse between markers using the footer arrows, if I start by clicking on marker "2023.01.01" (which is in Layer 1) and then clicking on the forward footer arrow, this will take me to marker "2023.01.03" (which is also in Layer 1) and not to "2023.01.02", because it is in Layer 2. The same behaviour happens when using the slideshow mode.

Describe the solution you'd like Maybe there is a way to change this behaviour as a user using the "Sort key" setting? If so I would be interested in knowing it, I did not manage to do it. Otherwise, in the "Slideshow" section of the settings, maybe add an option to choose if the features from all layers should be pooled before sorting?