Dr. Stefan Winkler
freier Softwareentwickler und IT-Berater

Today was not the first time, I made a common mistake with NatTable layers. And since it always takes a few minutes until I identify the problem, I'll post it here (as note to myself and maybe because it is helpful for anyone else ...).

The symptom is that when scrolling in a NatTable, it is not–or not only–the NatTable which is scrolling, but each cell seems to be dislocated in itself, leading to this:

NatTable messed up scrolling

The problem lies in my misinterpretation of the constructor JavaDoc of ColumnHeaderLayer (or RowHeaderLayer), which states for the second argument:

horizontalLayerDependency – The layer to link the horizontal dimension to, typically the body layer

It turns out, that I usually confuse the body data layer with the body layer. For my typical tables, the main part of the table is composed of the body data layer, the selection layer, and the viewport layer on top. 

The image shown above is usually the result of giving the body data layer as the horizontalLayerDependency parameter instead of the viewport layer (which is correct, because the viewport layer (as the topmost layer of the body layer stack) plays the role of the body layer in the sense of the ColumnHeaderLayer constructor's horizontal layer dependency).

So, should you ever encounter the above symptom, check your ColumnHeaderLayer and RowHeaderLayer constructor for the correct layer arguments.


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