Green marker

Ok, this has been puzzling me for long enough now so I will just ask, haha. What is this little green marker that pops up in seemingly random positions in my montages?

This represents the position of (next) playback start. Usually this is the same as the edit cursor, but this can be different.
See related menu:

Oh. Right, so I’ve played around with it a bit now and what I’ve found is that it works as expected if I open an audio file. The green marker goes along with where I move the cursor. If I open a montage, the marker comes up where the cursor is located, but then stays there. I managed to move it ONE time by selecting a range but after closing and opening the montage again that didn’t work anymore. Tried with several montages.

Am I missing something here or is it a bug?

It depends on the Transport setting. If you set a range, the green marker only change if you selected, as anchor, “Start or End of Range”.
There is also the “automatic selection”. In that case, WaveLab monitors your action and try to guess the best anchor. For example, if you select audio from left to right, the end of the selection will become the anchor.
if you select audio from right to left, the start of the selection will become the anchor.
If now you single click somewhere, then the cursor becomes the anchor.
The anchor is used as reference for Play From (F7) and Play To (F8) commands.

Got it. However, something seems wrong in the Montage then. With exactly the same settings for anchor (“Edit Cursor”), if I work with an audio file the anchor point goes where I place the cursor. In a Montage it doesn’t. If I go to the “Play from Anchor” menu and select “Edit Cursor”, the anchor point will move to where the cursor is, but will not update when I move the cursor. Setting “Play from Anchor” to for example “Start of Selected Time Range” works as expected, but not when set to “Edit Cursor”.