Suppose you mean jQuery Ui Javascript file. It is mot necessary to include jQueryUI when using jqGrid Bootstrap5. The only exception are the methods, which depend on jQuery UI – that are – sortableColumns, columnChooser, sortableRows and gridDnD.
You can use any function for loadError event, if I correctly understand the question. This does not depend on jQueryUI.
You can of course change the padding of the bootstrap table definition, bu we recommend to use the table-sm (small table) class in the definition of the table classes in jqGrid.
Te above can be done like this (after loading the jqGrid javascript file.