- Getting Started
-
Topics
- Wijmo
- Chart
- Map
- Cloud
- Gauge
- Grid
-
Scheduler
- overview
- Create and Bind Scheduler
- Configure Event Data
- Query, Filter, and Refresh Events
- Configure Resources
- Configure Views and Navigate the Schedule
- Create Advanced Layouts
- Synchronize Scrolling
- Configure Working Time
- Configure Time Zones
- Create, Edit, and Delete Events
- Drag and Resize Events
- Detect and Handle Conflicts
- Customize Event Display and Templates
- Customize Context Menus
- Hit Testing
- Keyboard Navigation, Focus, and Selection
- Troubleshooting
- OLAP
- Input
- Nav
- Viewer
- Tutorials
Troubleshooting
Use this page when Scheduler does not behave as expected. Each section starts with the visible symptom, then lists the likely cause and the checks that usually identify the problem.
Before investigating a specific symptom, verify that the host has a non-zero height, Wijmo CSS is loaded, itemsSource is assigned, start and end map to valid Date values, displayDate is set, and the active definition is valid.
The control does not render
The Scheduler area is blank
Likely cause:
The host has no usable height, the stylesheet is missing, or a module failed to load.
What to check:
Confirm that the host exists when FlexScheduler is constructed, has a non-zero height, and is visible. Confirm that @mescius/wijmo.styles/wijmo.css is loaded. For native ES modules, verify import-map entries for @mescius/wijmo, @mescius/wijmo.input, and @mescius/wijmo.scheduler.
The browser reports a module resolution error
Likely cause:
A package imported by @mescius/wijmo.scheduler is not mapped or unavailable in the build.
What to check:
Bundlers should resolve @mescius/wijmo and @mescius/wijmo.input from package metadata. Native ES modules require explicit import-map entries.
Events and dates are incorrect
Events do not appear
Likely cause:
The data source is empty, field mappings do not match, or dates are invalid.
What to check:
Verify itemsSource, mapped start and end properties, valid Date values, and start < end. Convert serialized server dates before binding. Set displayDate to a date covered by the data.
Event times are shifted
Likely cause:
displayDate, timeZone, or server-side UTC/local conversion is inconsistent.
What to check:
Confirm the Scheduler timeZone and the policy used to create each Date. Do not mix local-clock values and UTC instants without explicit conversion.
One event is displayed as several fragments
Likely cause:
The event spans multiple dates or resource sections.
What to check:
This is normal in layouts that split events. Treat fragments as one source item and update it.
Views and resources are incorrect
A resource lane is empty
Likely cause:
The event value, resource descriptor, and axis binding do not use the same field or identifier.
What to check:
Confirm fieldExpr, the value in dataSource, and the active definition binding. For multi-value resources, verify allowMultiple: true and an array-valued property.
A custom definition does not render
Likely cause:
Repeated axis identities or invalid Timed layout rules.
What to check:
Call planSchedulerProjection and inspect integrity.level and integrity.reasons. Timed layouts require one time:hour binding.
A custom definition has unexpected grouping
Likely cause:
time:hour shares an axis with another binding and the layout is normalized.
What to check:
Move the other binding to the opposite axis.
Working hours have the wrong effect
Likely cause:
workDays takes precedence over workHours, or the application expects non-working cells to be hidden.
What to check:
Clear or update workDays. Working-time settings style cells but do not hide them; use a time binding's visible callback to omit axis items.
Synchronized schedules drift out of alignment
Likely cause:
The two Schedulers use different definitions or different bindings on the synchronized axis, so the same scroll offset represents a different position.
What to check:
Use the same definition on both Schedulers, or keep the bindings on the synchronized axis consistent. Verify scrollingSyncDirection on the instance that holds the partner reference.
Editing and pointer interaction fail
Changes are not committed
Likely cause:
Validation or a cancelable event rejected the request.
What to check:
Inspect itemChanging and conflictChecked for args.cancel, verify start/end validation, and reconcile the collection after server rejection.
Dragging or resizing does nothing
Likely cause:
The relevant option is disabled or the layout does not support the operation.
What to check:
Verify allowDragEvent and allowResizeEvent. Summary views support moving but not resizing.
Conflicts are reported but the operation is allowed
Likely cause:
Conflict detection always runs. A detected conflict does not block the operation unless the application cancels the request.
What to check:
Set args.cancel = true in conflictChecked to reject the candidate. Keep server-side validation authoritative.
Display customization and keyboard behavior
Custom event content is unsafe or malformed
Likely cause:
Dynamic values were inserted into an itemTemplate HTML string without escaping.
What to check:
Escape user-provided values and base commands on the source item rather than rendered fragments.
A context-menu command is disabled
Likely cause:
canExecute returns false for the current target or action.
What to check:
Inspect hitTestType and call the base implementation for built-in actions.
Keyboard focus is lost after CRUD
Likely cause:
The item left the current view or replacement UI changed the document Tab order.
What to check:
Preserve the normal Tab sequence and verify the documented focus fallback.
Collect diagnostic information
When reporting an issue, include the active definition key, display date, time zone, item count, one representative source item, mapped field names, resource descriptors, and the browser console error.
Avoid logging sensitive event descriptions or location data.