- submit_label is the correct InlineForm option (not submit_text)
- Use wid:self instead of explicit widget id
- binds was incorrectly indented inside options
InlineForm and Tabular are siblings in the same VBox. Default
getWidgetById() searches downward from the source widget, missing
siblings. Use 'app.' prefix to resolve from root.
- Changed DataViewer to Tabular with row_options.fields for proper table rendering
- Form submit target changed from 'self' to 'billing_page' (root VBox ID)
with mode:replace, preventing nested page loading inside Form
- Fixed page_size to page_rows (correct parameter name)
- Added column definitions: date, time, subject, direction, summary, amount, balance
