Steps to Reproduce

1. load t4813.html with IE11 compatibility view
2. click the combobox button to open a popup

Current Result

iframe width shrinks each time when you open and close the popup

Expected Result

iframe width doesn't change

Debug Info

1. it happens when iframe width is not 100% or a fixed size.
1.1 The smaller percentage you specify, the more IE shrinks an iframe's width. For example, if you specify 98%, it shrinks a little a time, if you specify 90%, it shrinks more each time.
1.2 IE event shrinks the width when loading the page (before you open a popup). When zul page updates, e.g. "processing" appears and disappears, IE also shrinks the width.
2. iframes created by zk popup are not removed totally.
3. the iframe in parent HTML is not accessible and cannot be modified in a customer's use case
4. a datebox popup also causes the same issue.

Workaround

• https://docs.microsoft.com/en-us/internet-explorer/ie11-deploy-guide/fix-compat-issues-with-doc-modes-and-enterprise-mode-site-list
• set iframe width with "100%" from inner page by window.frameElement.setAttribute(), see the attached set-iframe-width.js