sorry to get back with the strange tableWidget behavior, but I tried something new.
I took the original demo file demo-tablewidget.html and added a new menu item in the demo-pane-splitter.html on my server.
I call the table page from the menu with
paneSplitter.loadContent('centerContent','table.html')
paneSplitter.showContent('centerContent')
and display it in the center pane. 1 table out of 3 doesn't have the right layout UNTIL I refresh the page.
Could someone please help me ? The same page loaded in a new windows displays perfectly.