vis: make core code more robust

The core vis code was originally written under the assumption that there
always exists at least one window. However, when being called from the
Lua configuration file during start up this is not yet the case.

In general, Lua code should always be placed within appropriate event
handlers e.g. vis.events.INIT for global configuration. Invoking API
functions depending on an active window from top level statements is
not supported. Where before the editor simply crashed, these changes
turn such code sections into NOPs.

Fix #561

0 files changed, 0 insertions, 0 deletions