Overview of common issues.
If content or a control is not visible, check in the DOM inspector of your browser whether the respective HTML exists in the document, or not. You can either search for the control ID or drill down the control hierarchy. It is often the case that the height has collapsed to zero, thus making the element invisible. A possible cause is if you have set no height for an HTML element, but set the height for a child element to 100%. The 100% refer to the height of the parent element with an undefined height, meaning that the child element wants to be as tall as its parent. You can also check whether the control and its parents are set to visible. Or, if you use data binding, check if the elements are properly bound. You can also use the support tool for this check.
Check the height settings of the parent elements. In CSS, a percentage height only works when the parent has a defined height. This issue is often caused by parent element with no height setting or again a percentage height and one ancestor with no defined height. In CSS, this results in a height that is collapsed to the minimum height accommodating all content. Some typical controls, however, adapt their height to the content are the sap.ui.core.View (all types) and the sap.m.Page controls. By setting the View height to any fixed height or setting the View and all ancestors to 100% height, you can define its height and 100%-height children will work fine. And the Page control can be set to enableScrolling: false: when scrolling is allowed, the scroll container in the Page control grows with the content, but when you want to set the content to 100% height scrolling does not make sense because by definition there is no scrolling when the content is as tall as the available space.
Check if the doctype is set correctly in your page. Some controls are not rendered correctly if the doctype is missing or is not correct. Table headers, for example, become exceptionally high.
Check if you have used custom styles in your application. If yes, they probably collide with styling in the theming libraries. One approach is to use the browser's debugging tools to inspect the element which has the wrong styling. You can usually see on the HTML tab which styles are applied to a DOM element. If you have styles in the list that your application adds, disable these styles in the debugger to see whether this solves the problem. Note that SAPUI5-specific CSS classes and IDs start with a sapUi prefix, for example, sapUiButton.
If this does not solve the issue, check for inline styles that are be applied to the element in the HTML code. You can also try to isolate the control from the application to see if there is an issue with the control instead of a collision of styles.
If none of the above solves the problem and the issue does not seem to be application specific, open a CSS message.
Although an issue in SAP-UI-CORE.JS is not impossible, the error often originates elsewhere. To find the actual issue, activate the SAPUI5 debugging sources. This enables you to see in more detail where the message is thrown and it gives you the opportunity to set a breakpoint at the corresponding line. From there, you can dig deeper into the problem and also have a look at the call stack to see where it has started.
In Internet Explorer 8, the native browser's context menu is not displayed if the handler of the context menu control manipulates the DOM. The context menu control also can prevent the native context menu. For this, SAPUI5 provides the possibility to disable dispatching the context menu event to the controls to show up the native context menu: Press CTRL+SHIFT+ALT and right click.