Buttonwidget can't interaction

I created a buttonwidget, when I set the buttonwidget on the rightupper view, it works well, when I click the button, the yellow color and the orange color changed .but when I set the buttonwidget on a leftbottom view, the button can’t change color when click. the codes are the same. why?

VTK widgets are a mess (extremely slow, inconsistent design, inflexible event mapping, not shareable between views, not visually appealing). We tried to use them for a couple of years and we ended up wasting enormous amount of time (hundreds of thousands of dollars). It’s not just us - most VTK-based applications don’t use them, VTK.js redesigned them from scratch, etc.

Finally last year we gave up on them and developed new version of the widget infrastructure - see results in Markups module. We could develop features that we have been just wanting to have for years. We still have some of the old-style widgets (plane and box) but we are getting rid of those, too.

We put general purpose buttons, sliders in the view header (see script repository for example of adding custom widget), which is also food because we don’t pollute the view with non-location-specific elements. Location specific items (points, lines, etc. in the view’s coordinate system) are interactive, clickable.