Environment
- mxcli:
v0.24.0 (2026-09-24T05:44:35Z), Windows (Git Bash)
- Mendix: 11.14.0, blank project from
mx create-project (MPR v2)
- Studio Pro: closed
Summary
Adding a tab to a page that already has a tab container is a common incremental change. Neither ALTER PAGE insert form accepts a tabpage, although the new tab page would be a direct child of the tab container in both cases. The only MDL route left is rewriting the whole page with CREATE OR MODIFY PAGE.
Reproduction
create module "ModT";
create page "ModT"."TabsPage" (Title: 'Tabs', Layout: Atlas_Core.Atlas_Default) {
tabcontainer tabsMain {
tabpage tpOne (Caption: 'One') {
dynamictext txtOne (Content: 'one')
}
}
};Then, separately:
alter page "ModT"."TabsPage" { insert after tpOne { tabpage tpTwo (Caption: 'Two') { dynamictext txtTwo (Content: 'two') } } };
-- Error: failed to insert: failed to build widgets: failed to build widget tpTwo: tabpage must be a direct child of tabcontainer
alter page "ModT"."TabsPage" { insert into tabsMain { tabpage tpTwo (Caption: 'Two') { dynamictext txtTwo (Content: 'two') } } };
-- Error: failed to insert: failed to build widgets: failed to build widget tpTwo: tabpage must be a direct child of tabcontainerExpected
INSERT INTO <tabcontainer> appends a tab page.INSERT AFTER/BEFORE <tabpage> places it next to the named sibling.
Actual
Both are refused. The insert seems to build the new widgets without their parent context, so the "direct child" validation fails even though the target is the tab container.
mxcli diag --bundle is available on request.
Environment
v0.24.0 (2026-09-24T05:44:35Z), Windows (Git Bash)mx create-project(MPR v2)Summary
Adding a tab to a page that already has a tab container is a common incremental change. Neither
ALTER PAGEinsert form accepts atabpage, although the new tab page would be a direct child of the tab container in both cases. The only MDL route left is rewriting the whole page withCREATE OR MODIFY PAGE.Reproduction
Then, separately:
Expected
INSERT INTO <tabcontainer>appends a tab page.INSERT AFTER/BEFORE <tabpage>places it next to the named sibling.Actual
Both are refused. The insert seems to build the new widgets without their parent context, so the "direct child" validation fails even though the target is the tab container.
mxcli diag --bundleis available on request.