If you want to use functionality like SPControl.GetContextWeb(Context).Lists and your trust level is set to WSS_Minimum the code will throw an System.Security.Exception telling you that:

Request for the permission of type Microsoft.SharePoint.Security.SharePointPermission, Microsoft.SharePoint.Security, Version=11.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c failed

This means that the code is partial trusted. Normally if you install your assembly in the GAC it runs with "Full" trust. Microsoft recommends that you install your web part assemblies in the BIN directory for a more secure deployment. Therefor the code becomes partial trusted and some functionality is prohibited by the CAS (Code Access Security) and the trust level set in the web.config...

Sometimes you decide to move a created Web Part to another namespace in another assembly. Whenever you do that the Web Part from the first assembly will still show up in the "Virtual Server Gallery" even if it is not present anymore in that assembly.

Solution
Go to the folder "wpcatalog" under your SharePoint web folder and there you will find a list with all dwp files from the "Virtual Server Gallery". Remove the old dwp file and refresh your browser. The Web Part will not show up anymore.

Thanks to my colleague Mart Muller for this simple solution :)

Todd Bleeker wrote an article in SharePoint Advisor Magazine about "Secure SharePoint Code Using Credential-less impersonation". He Describes a very cool method using the App Pool identity to complete tasks where the authenticated user doesn't have permissions for...

Patrick Tisseghem wrote a nice article about handling postbacks in web parts. This is always a problem in SharePoint. By checking the IsPostBack in the Page_Load member will often result in inapproproiate behavior...

On the blog of Mart Muller we can read that Microsoft announced a new office product for manage and use scorecards and key performance indicators (KPI's), and perform deep analysis all within an intuitive, collaberative environment.

http://blogs.tamtam.nl/mart/MicrosoftOfficeMaestroNew
ServerbasedBusinessPerformanceManagementScorecardApplication.aspx

For more information see the article:

http://www.microsoft.com/presspass/newsroom/office/factsheets/05-10MaestroFS.asp

I hope that this also will mean that the underlaying engine for development has gone through some changes. I have worked a lot with this engine and their are still some nasty issues there.

Lets hope and see :)

When you use properties you only have a few possibilities. Checkboxes are used for booleans, Text fields are used for doubles, int, strings, etc and a dropdownlist is used for enumerations.

So why not create your own ToolPart with default and/or your own controls? It is even not that difficult. :)

I'm working on a BirthdayWebPart which needs some functionality to select through a dropdown box the contact list. But only enumerations are shown using a dropdown list. So we have to write our own ToolPart...

I found a great article on SharePoint Thoughts posted by pBoy about adding a custom ASP.NET application into a site template. It describes in a few steps how to do this. Some knowlegde is needed because you will be modifying the ONET.XML. Follow the link below for the whole article:

http://www.bluedoglimited.com/SharePointThoughts/ViewPost.aspx?ID=167

Ted from Ted's sharePoint blog has written an article about enabling embedded pictures in the "Body" field of a discussion group. He got a question about this from Dave on the MS forum.

http://ms.mblogger.cn/tedteng/posts/14963.aspx

http://www.sharepointblogs.com/mkruger/archive/2005/05/06/1959.aspx

Some time ago Lamont Harrington wrote a nice article about SharePoint Web Parts and SqlClientPermission errors. In some cases when you develop custom web parts that connects to a SQL server you may be confronted with a nasty error. This is caused by the .NET Code Access Security (CAS). The following article describes a solution:

http://blogs.msdn.com/lamonth/archive/2005/02/13/372075.aspx

I'm always surprised that SharePoint developers do not often use more web part menus instead of adding ToolParts. The user doesn't have to go into edit mode which makes it more user-friendly. This article decribes a method for adding an item to the menu of the web part. The menu of a web part can be found in the upper right corner...