Setting button.visible makes it disappear

I put three buttons at the bottom of a page with various reports shown in listboxes. The buttons are for PDF, text file, or graph. Since not all reports can be graphed or have data likely to be sent to a text file, I put code to make two of them visible or not.
pbText.Visible = True
pbGraph.Visible = True

When this code runs, the two buttons disappear. It seems to be a bug, but it is hard to replicate. I created a new project with three buttons and entered code to make two of them visible, but it worked as it should. Should I be making a bug report about this and sending the project to Xojo? The binary source is about 1.5 MB and it needs a database and password to get into it. My workaround was to change .Visible to .Enabled. Not perfect, but acceptable.